Inside jokes are a kind of legacy. Twenty years later, one word still makes the whole group lose it.

A shared joke is a piece of private history that only functions for the people who were there. It compresses a whole evening into one syllable and keeps working long after everybody has moved, changed jobs, and stopped talking weekly. The joke is not really the joke. It is proof you were all in the same place once.

Do not let the current ones die from lack of use. Say the stupid word in the group chat for no reason. Whatever is forming now with the people around you is what still works in twenty years.