I try not to be rude and cut people off in line, sometimes it’s difficult since two people arrive at the checkout at the same time and it feels like, ok who was first to arrive and should go first. In the past I will let the person behind me go first if they have 2 items and my cart is full, but then a few times when I arrive the same time as someone else I feel guilty for going ahead of them. Sometimes I will ask too, and say are you in line and sometimes they’re not.