that really is a problem with the funny bone, if it tickles it tickles, if it doesnt it doesnt. I find george carlin funny, robin williams, dave chapel, they are all funny, blackadder, red dwarf. some jokes you can laugh at 100 times, others only a few, some, not even once. also, its the way you construct the joke, the way you tell it.

theres a farmer, hes had the same employee for 15 years, and they have a great working relationship. the problem is, they dont know a single thing about the other. the closest they come to a personal conversation is, good morning, how was your weekend?
one day, the farmer's employee buys a moped. taking this as an oppertunity to start a personal conversation, he asks, new moped?
the employee looks angry at the farmer and walks away steaming mad. the farmer watches him storm off, flabber gasted.
the next day the employee walks up to the farmer, and hands him his resignation.
the farmer looks questioningly at him, and he replies, all that nagging about my new moped!

i think its setup, development, twist-in-the-tail, something you dont expect.
a one-liner is mostly a mix up in what a word should mean, then giving it a new meaning, or a strange context, a longer joke just has more setup, in the way of explaining the two opposite frameworks.

monty python was bad that way, they had poor punchlines, or no punchline all together, but they did get closer to discovering the funny bone. they had a thing where they would suddenly blurt out the word tea-pot. that became funny after awhile, because it is nonsensical.

even subject matter might be important, if its close to your heart it might just sound insulting. if you don't care about the subject matter at all, your reaction might be, and?

While on a road trip, an elderly couple stopped at a roadside restaurant for lunch. After finishing their meal, they left the restaurant and resumed their trip. When leaving, the elderly woman unknowingly left her glasses on the table and she didn't miss them until they had been driving about twenty minutes.

By then, to add to the aggravation, they had to travel quite a distance before they could find a place to turn around, in order to return to the restaurant to retrieve her glasses.

All the way back, the elderly husband became the classic grouchy old man. He fussed and complained and scolded his wife relentlessly during the entire return drive. The more he chided her, the more agitated he became. He just wouldn't let up one minute.

To her relief, they finally arrived at the restaurant. As the woman got out of the car and hurried inside to retrieve her glasses, her husband yelled to her, "While you're in there, you might as well get my hat and the credit card." [forwarded by Fred Dick]

is that funny? now lets say you have to live with that guy...