Well, you do, don’t you? Thing is, for some reason, many authors seem to lose sight of this quirk of human nature when they’re writing dialogue. Guessing at their motivation, it appears they’ve created a rule which decrees that a serious scene must contain earnest interchanges between people who are treating the whole matter with the gravity it deserves.
But people do laugh – all the time – including in such tense situations. That’s part of being human and (frequently) a key part of staying sane. Thus your detectives clearing up the aftermath of their serial killer’s latest rampage will find something to joke about, the rival for your heroine’s affections will use wit to snipe at his counterpart, your family drama will have an in-house jester who makes wisecracks to help themselves and others overcome the more difficult moments … and so on.
Jokes don’t need to be funny. In fact if they’re too funny, they’ll sound false. Real people aren’t professional comedians and they’re prone to goofing up punch-lines – maybe you’ve done so yourself. You might not even want the listener to be amused: they could be irritated, have heard the joke before, find it embarrassing etc. On the other hand, they might roar with laughter or quip back with a joke of their own.
Here’s some homework to leave you with. Listen in to a conversation of significant length that’s taking place around you. How much humor can you spot? What percentage of the overall dialogue do you estimate that to be?
Now put that data to good use when you write your next book. I look forward to reading it!