Flying CPH-HEL on SK a few weeks ago I sat on the bench and waited for everybody else to board. About half way through boarding a man approaches the queue from the opposite direction and squeezes his way in. On GA notices this and tells him to stand in line like everyone else. The man uttered something about being the back rows but the GA insisted and so he took a few steps back (but not to the end of the queue).

I hate people cutting in line or other ways being selfish so to me this was nice to see.