Resentment is a kind of anger. With this much, everyone agrees. It is also widely agreed that anger we call “resentment” predicates some kind of wrong at the hands of other human beings, and that it is in some way a defensive emotion in its operation or its manner of expression. Resentment is both a reaction and a signal. It warns or threatens someone who is perceived as having crossed a line or done something unacceptable. It shows them that we have noticed that, and it shows how we are now disposed toward them. Someone insults you; you say “I resent that.” You mean that you take it as an affront or offense to you, and you are “calling” the offender on it, issuing a challenge, putting the person on notice, possibly on notice of unpleasant or retaliatory action in return. Once resentment is expressed, it can mean that further confrontation is about to ensue, or that payback is on the agenda, or that you won't be speaking to the offender again, short of an excuse, explanation, or apology. But can't I resent the fact that it rained on my picnic, or that you are taller than I am, or that my neighbor drives a nicer car than I can afford? Here no one seems to have done anything wrong, and in the case of rain and relative height, it's not clear that any responsible party has done anything at all, much less to me.