Some people seem to go vegan because they're emotionally off-kilter. I'm in a few vegan Facebook groups and I've seen posts where people are way over-reacting to food cooked on the same surface, or talking about their emotional breakdown over the suffering of animals. I'm vegan almost two years and I'm pretty sure I ate mayo on a burger two weeks ago. I ordered it explicitly without, but sending it back would just create waste and no benefit.