Max:
This may be YART, but it seems to me I waxed prolix here on my theory of humor some months ago.
In a nutshell: EVERY joke at which you laugh or want to laugh is at the expense of something or someone. Usually a someone. Not most jokes. EVERY joke. Blonde jokes, black jokes, Jewish jokes, whatever, they all put someone down. If a joke doesn't put someone down it's not funny. It's a simple matter of holier than thou.
Puns, though, are not jokes. Some people will say there's nothing funny about a pun; in a way they are correct. What there is about puns is an innate cleverness.
I tell jokes all the time, but I understand that they can be hurtful, so I am almost always extremely cognizant of the listener. For example, I will never ever make a joke about an individual's name. That's a direct attack on the person. The teller may think it's funny, but not the butt of the joke.
I am much less "careful" about telling a pun or shaggy dog story, only ascertaining beforehand that the person I'm telling it to is going to get it.
One of the funniest stories I ever heard was about Jesus' interactions with a guy who was making him a new robe. Jesus and the guy went into business as Lord and Taylor. I made the mistake of telling it to my brother-in-law, who is well-educated (but not very bright if you get my drift. He did not know there was a department store chain called Lord and Taylor. Dan's not on my a-list as a recipient of puns, I can assure you.
Ted
