I've always found some solace in not being wasteful. In theory we're working towards a better future - harming animals now will result in world with no harm for an infinite number of descendants later.

This is more or less "do the ends justify the means", but we live in a zero sum universe, so every action we take has to answer this question (if I eat this food, somebody else can't eat it). It's a matter of determining what we think justifies the cost.