A joke that needs “relax, I’m kidding” right after wasn’t really a joke. It was a test.

A joke that needs a disclaimer was carrying something else. Telling somebody to relax recasts what you just said as their overreaction, which is a tidy way of getting the sentence out while making its effect their fault. Often it was a probe, to find out how much can be said about a person while they keep laughing.

Notice if you have been reaching for that phrase, and ask yourself what you were testing. Try saying the real thing straight, or not saying it. And when it is aimed at you, you are allowed to answer that you heard it fine and did not find it funny.