Oh that’s a good one.

Parallel: Sometimes a player joins that throws off whatever alchemy was working before. Now everyone has less screen time, or the noob has problems/questions about problematic rules that everyone else has agreed to gloss over. Or personalities change juuuust a tad at the table — the new player introduces a little casual sexism/racism that hadn’t been there before, or laughs off the stuff we were treating as srs bsns.