There's a time and a place

Addl wisdom: some people make jokes when they're uncomfortable, as a defense mechanism. If you have a player or players constantly trying to lighten the mood, consider that the atmosphere you're trying to create may not be a good fit for your party, and/or parts of your party may not be a good fit for your game.

thankfully i have no idea how to make a good atmosphere in a game so that's never a problem

Heidi has truly the best wisdom.