British middle class manners pretending something distasteful doesn’t exist / hasn’t happened.
I mentioned upthread I made a joke that I thought was very old and obvious when I smashed my finger and ended up in the ER. I asked the doctor “will I be able to play guitar when it heals?” He said “Absolutely”. I said “great, I wasn’t able to before!” (It’s a joke that goes back to Vaudeville days). I thought I’d get a groan, but I got a genuine laugh. It probably helped that the ER doc was pretty young. Every old joke is new again, eventually!
The defense of dads everywhere who make their five-year-olds giggle with the hackiest, hoariest shit. Myself included. 
They say that kids are easy audiences for not only dumb, obvious jokes, but also for playing music to. Since they don’t know any better, they’ll think you’re a great musician even if you’re a rank amateur, as I am.
But I used to sing and play guitar to my older son when he was no more than 5 or 6. Songs like 'Yellow Submarine". He said “You’re not very good, dad”. 
When I’m walking Huck, my Great Dane, I can’t count the number of times I’ve heard - Where did you get the pony? or Is he part horse?, Can you ride him?, etc. 
When looking at the ocean or sea, I’ve asked someone, “is it saltwater?”. After they answer and I explain I was just fucken with them, I’ve been told people as it seriously.
Arther a few LARGE draft beers, if I want just a bit more, I’ll ask for a child’s size.
Did he come with a saddle?
We never have had a Great Dane. We have had a Great Pyrenees.
Years ago I bought a used motorboat from a father and grown son who, as a side hustle, bought used boats, fixed them up and resold them. As I was a rank novice when it came to boating, the father generously helped walk me through some boating basics: how to tie a bowline hitch, tips for backing up the boat to launch, etc. Then he went through the boat control basics: forward throttle, reverse, how to raise and lower the outboard motor, lights, etc.
I jokingly asked “where’s the brake?” and his jaw literally dropped open. He clearly was thinking “wow, this landlubber is even stupider than I thought”. I quickly said “Just kidding!”
Yep! I’ve heard that one too.
A stupid, obvious joke I feel compelled to repeat whenever the context arises: if and when anyone asks me (as they inevitably do) “What’s up?”, I point at the ceiling or sky, and solemnly reply “That”. Of course, I’m also the sort of wiseass who, when someone says “Give me a hand with this”, claps his own hands a few times.
What?
We hung out today with our Sint Maarten friend Juggie, proprietor of Juggie’s Place, the smallest bar in the world.
Luckily someone who stopped for a drink asked, as many do, why they call him Juggie.
Ha answered, as always, with a serious expression, “My name is Jagdish Kumar Amarnaney, what the fuck should they call me”.
“Do you have reservations?”
“Yes, but we decided to come anyways.”
I can’t ever resist.
There’s also "Has anyone ever told you that you look like…?
I stopped doing that many years ago though. There was a maintence guy in a university setting I met when he came in to work on an oven. I swear, he looked so much like a young Paul McCartney I couldhn’t help myself. I started "Has anyone ever told you? and before I could name he said, in a rather sharp tone, “Yes.”
Oh, and I’m from Kansas. While I was in the military, and would be asked where I was from, I got so sick and tired of Oz jokes.
Finally, a tired joke I’ve never heard. Thank you!
I shall add it to my repertoire. 
We have a butterfly garden (a bunch of stuff planted to attract and benefit butterflies). It really works well.
When the backyard is filled with butterflies and a visitor comments, “oh my, look at all the butterflies”, I’m unable to resist sighing and replying, “yes, I need to spray”.
I make the same comment for, “look at all the squirrels” or anything similar.
How Addams of you.
Possibly non-obvious joke:
Young child to her grandmother: ‘Look at all the pretty white butterflies! My teacher said that butterflies are all precious and must be protected!’
Grandmother, sighing: ‘Your teacher buys her cabbage at the store.’
(I do keep a lot of habitat, including milkweed, that’s useful to other butterfly species.)
I can only go by me.
“Cold enough for you?”
“Did you sleep well?”
“No, I made a few mistakes.”
Slept like a baby. Woke up every 2 hours and wet myself.