A sudden, unexpected bipolar swing from your mother. She goes from being warm, friendly, generous, loving, and sweet to a quiet, pissed off beotch who drills you on personal details and gets angrier if you don't answer. Her hands may clasp behind her back in an obvious fashion. She'll respond with answers like "K" and "...very nice." Her intent is to make you feel like you have something to be sorry about even though you most likely did nothing.
We experienced heavy mom mood when I came home from the concert.