Inspired by this thread in GQ. I was all set to weigh in with another vote for “mine ain’t, and I’ve never had a problem,” but there were already a dozen or so people who’d said that.
So – let’s do a poll!
My mom and I argue about this - IMO there is a difference between signing my name and a signature. If I have to sign my name, it’s legible. If something requires my signature you can read the first letter or two in both my first and last names. She, OTOH, writes both as she learned in grammar school 60 some years ago.
If you can read mine, it’s a forgery.
Over the years I’ve gone from pretty legible to now. I’m down to three letters, first of each name and the last of my last name. But the squiggles in between are consistent.
My signature evolved from a stylised writing of my name to the shape of an ant over years!
My signature is not consistant. As far as I can tell, nobody’s really is - everybody in the receiving dept automatically spells their name out for the UPS and FedEx folks…
As stated in the other thread, my signature really does involve me spelling out my full name, so even though it’s a bit messy, you can distinctly read my first name, middle initial and last name. I think it throws off merchants, but my signature has been the same since I was about 16.
It’s mostly my first and last name initials, overlapped, with a squiggly tail that’s less squiggly as it trails out. So usually you can make out two letters.
You can read the first letter of my last name but I’ve been told that my first letter of my first name looks like an 8 and over time I’ve come to draw it that way more and more, at least it’s distinctive.
The first letter of the first and last name are legible. First name a couple more letters may be distinct but it varies, last name after the first letter its just a wavy line.
Thanks, I needed someone to co-sign for a loan. 
I’ve read that messy signatures are actually a lot easier to forge. Any truth to this, someone?
Wow, so far I’m the only person (out of 32) whose signature is just written in regular handwriting? I know that my signature is unusually neat, but I didn’t think it was that unusual.
I think it may be because my name gets butchered enough as it is; I’m trying to reduce that likelihood. (Usually unsuccessfully.)
I chose option 2, since I normally write in manuscript, but my signature is in cursive.
Every so often I try doing the illegible version, but I can never do it anywhere near the same way twice. On the other hand, my signature from 8th grade looks the same as mine does now.
I’m occasionally told that I should have been a doctor.
It is a completely illegible scribble, and has been since I can remember. It was originally based on the letters in my name, but bears no resemblance anymore.
If I’m signing something important I’ll print my name under my signature as well.
So illegible that I didn’t have to change it when I changed my last name.
You can read the first letter of my first and last names, and (if you know what you’re looking for) my middle initial. The rest of it may as well be morse code - a short series of near-horizontal lines of varying lengths.
This is pretty much what mine looks like, the first letters and that’s about it. I’ve also been told a number of times I should have been a doctor. Maybe I should have been.
Well, with my signature, you can pretty much tell that the first letter of the first name is an ‘n’, and may be able to tell that the last letter of the last name is a ‘y’. Everything in between, though? Not so much.
My hubby’s sig, OTOH, looks just like he wrote his name, in cursive, in his normally bad hand-writing. I’ve gotten really good at forging it! 
Ironically, when it comes to just everyday handwriting, mine is much nicer than his!
Note to anyone who may take the ‘forgery’ comment seriously: If checks or money orders for our rental properties, which I manage, are made out to him, I will “sign” the back so they may be deposited. I do this with his full knowledge and blessing!