If his name sounds Italian and people call him “godfather” - don’t piss him off.
From Friday, by Robert Heinlein: “Never wound a police officer.”
From Batman…
“Never rub another man’s rhubarb!” -The Joker
“The future is whatever you make it – so make it a good one.”
–Doc Brown, Back to the Future Part III
“Be excellent to each other and party on.”
–Bill and Ted, Bill and Ted’s Bogus Journey
“Do, or do not. There is no try.”
–Yoda, Return of the Jedi
And just about everything written by Terry Pratchett… 
Dont mess with a man who has a pig farm. - snatch
Who? Never heard of him. Has he written anything else?
I can pat the bunny!
You can’t take it with you–exactly what the movie title says. Enjoy the hell outta your life and don’t get bogged down with “stuff” and what other people think.
“Tests are gifts and great tests are great gifts.”–Bujold, from the Barrayar series.
There are lots more but those are the two bunbbling up through the ooze, i.e. the swamp that serves as my mind lately.
Veb
LADY PRESENTER: Well, that’s the end of the film. Now, here’s the meaning of life. [takes envelope] Thank you, Brigitte. M-hmm. Well, it’s nothing very special. Uh, try and be nice to people, avoid eating fat, read a good book every now and then, get some walking in, and try and live together in peace and harmony with people of all creeds and nations, and, finally, here are some completely gratuitous pictures of penises to annoy the censors and to hopefully spark some sort of controversy, which, it seems, is the only way, these days, to get the jaded, video-sated public off their fucking arses and back in the sodding cinema. Family entertainment bollocks!! What they want is filth: people doing things to each other with chainsaws during tupperware parties, babysitters being stabbed with knitting needles by gay presidential candidates, vigilante groups strangling chickens, armed bands of theatre critics exterminating mutant goats… Where’s the fun in pictures? Oh, well, there we are. Here’s the theme music. Goodnight.
Seriously. Monty Python played an important role while I was growing up. Behind the jokes, I thought they were very serious about the world (Mad magazine was an earlier, major influence, too).
Here’s one more bit:
[board meeting]CHAIRMAN: …Which brings us once again to the urgent realisation of just how much there is still left to own. Item six on the agenda: the meaning of life. Now, uh, Harry, you’ve had some thoughts on this.
HARRY: That’s right. Yeah, I’ve had a team working on this over the past few weeks, and, uh, what we’ve come up with can be reduced to two fundamental concepts. One: people are not wearing enough hats. Two: matter is energy. In the universe, there are many energy fields which we cannot normally perceive. Some energies have a spiritual source which act upon a person’s soul. However, this soul does not exist ab initio, as orthodox Christianity teaches. It has to be brought into existence by a process of guided self-observation. However, this is rarely achieved, owing to man’s unique ability to be distracted from spiritual matters by everyday trivia.
[pause]
BERT: What was that about hats, again?
Says it all, I think…