Hate: Other people
Love: When there's no one next to me in first class. Or if the husband is flying with me - then I don't have to deal with other people. I make him do it.
If there is another person next to me in first class, I can sort of handle it kind of. If I have to fly in coach and there's a person next to me, I will sometimes rebook to a flight that has two empty seats because fuck other people getting all cramped next to me.
Also, pro-tip - if you're going to fly and there's no first class/you can't afford first class, always *always* buy the upgraded seats and find a row that has two empty spots in it. If the only thing that's left is a middle seat, ain't no one paying to upgrade to a middle seat. The only "meh" to that is, if there are standby passengers, they may get stuck next to you, but of the last 4 flights I've taken in the past couple months, I was either in first (with people next to me, ugh) or I had an empty middle seat next to me.
If people put their seat back, don't get mad at the person reclining, but definitely write the company and let them know. If enough people bitch, hopefully they'll take away the ability to recline. Rule-of-thumb - people are douche bags, and doubly so on airplanes because fuck you they have to be comfortable and they couldn't give two shits about you.