I had an annoying co-worker once who told the most outdated, unfunny jokes I’ve ever heard. Stuff that would have made even Jay Leno groan and roll his eyes. Things like “I hope this rain keeps up!” Why? “Because then it won’t fall down, yuk yuk yuk”. :rolleyes:
He once looked at me and said “don’t you laugh?”.
“At things that are funny, yes” was my response.
My laughter must be earned!
Aside from being polite, it’s usually good for communication to at least acknowledge that you recognize something was a joke. Otherwise, the teller might think you think he’s being serious, which depending on context can get confusing and/or tense.
Plus, yea, you come off as kind of a dick if you just do the stony silence thing. And the standard for acknowledging a joke is pretty small. I usually just give a half smile, to let the other person know I realize they were making a joke and at least pretend to be slightly amused.
If you’re on a first or second (or third) date, yes, you laugh and you make it sound real.
The worst is when customers try to joke weakly over the phone. I don’t have the option of smiling quasi-sarcastically or rolling my eyes for the benefit of someone who can’t see my face. I work at a bank, and can’t count the number of times this exchange has taken place:
Me: “Is there anything else I can do for you today?”
Customer: “Sure, transfer a million dollars into my account! hahaha! I’ll even give you half!” 
Me: :dubious: :rolleyes: “Thanks for calling, have a nice day!”
Come on, you lame fuckers, stop being so fucking lame. I can only fake-laugh at your tired old yarns so many times before putting a bullet in my brain starts sounding like a better idea.
If I were better at being a dick (and wouldn’t get in trouble for it), I’d prefer to play it deadpan and say, “That would be fraud, sir. Anything else I can do for you?”
Why laugh at a lame joke? Screw that; this doesn’t mean be an ass and do assholie things while not laughing.
That being said a lame joke doesn’t mean that the teller of the joke is at fault, it could me. If an audience gets ajoke and I do not, well then the issue is probably not the audience or the comedian.
just be on the watch for people just fucking with you to see how many times you fake laugh or whatever. they know the joke is lame for example, and are just seeing how many people will play along with a fake laugh and for how long. they are amusing themselves and maybe friend(s) they’re with. even worse, they may have everything being recorded on their phone to upload to youtube or the like later. people not in the best mental states will sometimes do stuff like this (or simply trying to get popular on the internet) - particularly to people they see as ‘better off’ than them or who ‘have it made’.
also drunk people in particular can start out legitimately trying to be funny but may get the message (alcohol-delusional* or not) that their jokes aren’t funny and ‘get aggressive’ so to speak, and flip into the mode where they are just fucking with people, utilizing passive-aggressive techniques to turn a (seemingly or not) foul situation into their own amusement at least.
**hereforeto is a term, if not already coined, that is as of now coined by me. the definition is the opposite of heretofore.
/armchair psychiatrist
There’s strategic politeness & tactical politeness.
For somebody you’re likely to deal with just this once, strategy is irrelevant. So be tactical and be polite & smile to fake-laugh as you can. It lubricates the situation at no real cost to you.
For somebody who’ll you’ll be dealing with for the indefinite future, e.g. co-worker or neighbor now you’ve got a decision. Just being tactically polite is strategically stupid since it is encouraging behavior you want to discourage, namely the unskillful telling of inappropriate or incompetent jokes.
So do the strategically smart (and strategically polite) thing. Tell them they aren’t funny & the sooner they stop acting like a kid and insulting the intelligence & patience of their audience the more well-liked and influential they will be. That’s advice they can use to benefit themselves.