Now, there are people I like and people I like less, there are people whom I agree with more, or less, but there is nobody right now for whom I feel enmity beyond that. If someone were to wish me harm, then I would be an enemy for that person, but I am not obliged to wish harm on that person. I would try to protect myself, but that is it.
I'm sure I could feel enmity under extreme circumstances, but it would take something very serious to do it. If someone gets angry at me, I don't have to reciprocate; nothing obliges me to. Looking back, having enemies never actually benefited me in any way, even if my feelings seemed justified at the time.
(I do feel some anger against that poet who passes off his own work as that of others in a kind of reverse plagiarism. People like anger because it gets them excited and hence not bored. I'm no different in that, but often in retrospect it seems stupid. I spent a lot of energy dissing Luis García Montero and defending myself when others didn't like it. It is fairly exhausting!)
Of course, you could say now that I am powerful, so that few people are in the position to do me harm anyway, so in that sense my letting go of the idea an enemy seems logical and not particularly virtuous. That's a fair criticism. So do vulnerable people need enemies? Does the concept help them. It could. In my experience, when I had enemies it was when I felt vulnerable myself (before tenure), but I think I would have been better off enemyless even then.
What about Trump, then? Surely negative feelings come up. I should do things to counter his influence and work against the things he promotes. The negative feelings themselves are justified, but they have zero effect on Trump himself or his power. In fact, the seething anger against him just seem to bolster him.