To me, #1 would be when the person in front of you lowers their seat- to your lap!!
I came off a flight yesterday. I wish the seats would recline enough to be in your lap. They move back maybe 2, maybe. There is no way it would be in your lap. Ive been traveling commercial almost 30 years. People who get bent out of shape for people who recline their seat should, just, recline their own seat. See, problem solved!!
I think that they should eliminate the recline completely. If it only goes back 2" then why should anyone feel the need to recline? It's a psychological trick: Oooh! I get to control some minor aspect of my environment by reclining the seat two whole inches! Aren't I the BMOP (Big Man On Plane).
The airlines could significantly increase safety and also save costs if they got rid of this annoying nuisance that gives a few people a false sense of control, while making may others much more miserable, especially given the ever narrowing space between rows.