I have no problem with my legal name (Robert), but everyone calls me Bob, which is also fine. Well, except for my brothers and guys from the old neighborhood, who call me Bobby. It’s all good.
Diminuitive all the way. People call me ‘Ass’.
Joking aside, both my wife and I go by a diminuitive version.
I can’t even sign my full legal name. My handwriting is crap to start with, and you want me to do what? In cursive? Nope, can’t do it never have. I just don’t.
I prefer to be addressed by a diminutive of my first name, but if my name is in writing—especially when combined with my last name—I prefer my legal first name.
Especially at work. I actually get a little annoyed when I get a formal letter addressed to me as Mr. [Nickname] [Lastname], PE.
And with anything involving travel, I never even mention my nickname. It’s otherwise far too easy to end up with a mismatch between my reservation and my government ID or passport.
They call me “Michael” or “Czarcasm”, but almost never “Mike”.
This sounds like a puzzle. I’m going with “Joshua”, “Joshy”, and “Josh”.
Or maybe “Timothy”, “Timmy”, and “Tim”.
Ok, I actually have no idea, and I’m just guessing. You don’t need to answer, of course.
(And all along I thought your legal name was Elmer J. Fudd. 
What does the “J.” stand for anyway?)
I was given an Anglicized version of my paternal grandmother’s name as a middle name, and a very common (in English speaking countries) first name. In my twenties I started using the non-Anglicized version of my middle name. If I’d realized how fussy the USA was going to get about exact names some 30 years later, I’d have had it legally changed when I’d only have had to coordinate one bank account, my driver’s license, and the tax and social security people; but by the time it started to matter there would have been so many things to coordinate that I was afraid something would get screwed up, and on any given day it’s always easier to explain to whoever knows me as Preferred Name why I’m handing them a document that says Legal Name than to try to get it straightened out legally.
Which means that when a clerk in a store has been instructed by management to call me by first name in every sentence, it’s even more annoying than this is for most people, because they’re going by the name on the credit card so they’re calling me by the Wrong Name.
Lately I’ve noticed that some places have recognized this sort of problem and will have a place on forms for “preferred name” as well as for your legal name.
I get it all around. My immediate family calls me by my full middle name. Mostly everyone who has met me since I left home call me by a diminutive of my middle name. People who know me indirectly (mainly friends of siblings) call me by a diminutive of my first name. And I get a fair number who call me by my (rather short) last name. I’ve never been picky about labels. I answer to all.
I stopped using my first name early on. I managed to turn it into an initial only when I applied to college. I legally changed my name before graduating. All my documentation was changed as well, though two arms of the government chose different middle initials of the two middle names. I recently changed my birth certificate to match my legal name, but haven’t told anyone in my family because it would upset my mother.
I don’t like diminutives of my name, though I don’t correct a few of my friends to whom it seems to matter that I should have one.
All of the above depending on who is talking to me.
My mother was the one person I knew who got an exemption to keep using my first name. She hadn’t gotten along with my father’s mother and I wasn’t going to try to make her use that name for me.
I always hated my first name.
When I married long ago, I got the best last name ever.
You can only spell it one way.
A few famous people, male and female, have it as their first name. I tell people, call me this, its my last name.
When I tell them my first name some insist on using that. Unmannerly.
My first name is one syllable, but I’ve never used it. My parents always called me by my second name.
However, whenever I go to the doctor, a pharmacy, etc, and have to show my medical card, I get called by my first name. I just roll with it.
That’s also what people who know me from one of my universities call me as, because by the time I arrived my first name was firmly entrenched in all the class lists, student lists, etc. It was too much bother to try to change a university’s records, so for a year I was “Firstname”.
My second name is a family name, but has a common diminutive that my parents called me by. That’s what pretty much everyone knows me as.
But that diminutive can also used for another given name which is relatively common. So when people I don’t know very well sometimes try to be more formal or polite, they call me the long form of that other name. I just roll with it.
My last name is a Scottish family name that in North America is sometimes used as a given name. I sometimes get called by that, especially if the person sees my middle name which is normally used as a last name, so I get called “Lastname Middlename”. I just roll with it.
This article has been posted before:
I’m known by my legal name, since there isn’t any real diminutive for my name- some people have tried to call me “Dee” but that’s more of an initial than a diminutive or nickname. My mother used to sometimes call me “Dori Ann”, which annoyed me because 1) It was a completely different name , not a diminutive and 2) she got to choose my name, so she could have just named me Dori Ann which I actually would have preferred to my name.
I think the reason for the question is because it isn’t always a matter of " I’m known as “Dave” because that’s what the neighborhood kids called me.Sometimes it’s "My parents named me “Robert” but called me “Bobby” because they thought having my legal name be “Bobby” might cause me trouble later in life* or to distinguish me from my father/uncle/grandfather/ten cousins who were all named after our grandfather - and then when I got to be 13 or so , I started going by “Rob” so that only my family and childhood friends call me “Bobby”
* My husband 's legal name is the equivalent of “Billy” and he forever has trouble with people making checks out to “William” or calling him “Bill” because they think “Billy” can’t be his legal name, and of course someone whose legal name is “William” who goes by “Billy” won’t mind being called “Bill”.
I don’t dislike my legal name at all (it’s quite common, especially in my age group), but my parents immediately used the standard two-syllable nickname* (also very common) and that’s what stuck – and is what I’ve always preferred. I’d only hear my full name when I was in trouble. But when I was 27 and moved out of state to start my first “real” job, I tried going by my full name because I thought it sounded more professional/adult: soon, though, I realized that it doesn’t quite fit me. It feels too formal. And the one-syllable nickname has also never felt right: it doesn’t bother me, but I never ever think of myself by that name. So I went back to fully embracing the two-syllable nickname, and these days (I’m now in my 50s) even my work badge and email address use it.
Like others, I deliberately use my full name when traveling – or in any circumstance when the name I provide will be checked against an official form of ID. No one would think I was trying to use an alias or anything; it’s just easier. I also tend to use my full name when subscribing to/ordering things.
*They did the same with my brother, who has an inoffensive legal name but has only ever gone by one particular nickname. His full name has two completely different common nicknames, and every now and then someone tries to address him by the other one – which happens to be a homophone of our dad’s name (hence it never being used in our family) – and we’re always genuinely like, “What?? Who??” 
My mother named me Elizabeth so that I would have a litany of nicknames to choose from. She believed she would call me Libby because she thought it was cute. According to her, she took one look at me and knew she would never call me anything besides Elizabeth.
So I have always been Elizabeth. I love my name, and I despise (almost) anyone who calls me by a diminutive. The exceptions are my Grandma who called me Liz-a-biz, and an older coworker who called me Lizzy Lou.
I’m Gareth or Garry. But on the first day of primary school the teacher ask my name and I said Gareth or Garry, and she said they already have a Garry so I’d be Gareth. Since then I’ve been Gareth to everyone outside my family, but Garry to my family.
I used to not care for my legal name when I was young because it is slightly unusual in an American context. Now I sort of like it because it is slightly unusual in an American context, though becoming very mildly less so with time.
But it still reads as female to a majority of Americans, especially the non-cosmopolitan sort and I’m not. So I go by a single-syllable diminutive that is unambiguously male (in an American context) just for the sake of avoiding the frequent confusion and occasional mispronuniciations
I had to legally change my name in order to be known by it (formerly my middle name), but I very, very rarely get a nickname. The cousin I’m named after almost always gets the diminutive, but I never do, and it’s not to distinguish us, since our last names are different and we’ve always lived thousands of miles from each other. Two people have shortened it on occasion, which I liked, but most don’t.
I don’t hate my given name, but I use my nickname for everything but legal documents. I do prefer it.
Like the OP, I have a name that is pretty common to shorten (and a lot of people think my name is Dave/David, for some reason), but I have never gone by the long form. A couple of aunts - long deceased - used to use it, and a couple of my cousins still do, but most everybody calls me by the shorter variant.
My dad, however, has a much different story. He was born in the US, but was given a Japanese name at birth. When he was in elementary school, however, he was ‘given’ an “American” name by a teacher. (Same teacher re-named all his younger siblings, too). So within the family, he was known by his given name, but in school he was known by either his American name or one of the common nicknames for it (as in Jonathan/Jack). To my knowledge, though, he never officially adopted his American name. I have no idea what his passport said.