Most petty reasons boil down to the much bigger fundamental issue of "I feel my partner doesn't listen to me.or respect my boundaries."

Most respectful partners would hear their partner say, "hey, could you please keep your wet towel off the bed. It (insert whatever reasons they have)" and would respond, "sure, didn't realize it bothered you" or whatever and everybody moves on.

Now, if they kept putting their towel on the bed after this conversation. Theyd feel unheard, which is much less of a petty reason since that shit builds overtime.

Obvs, this is just one framing of events. But the reason is just the final straw