You forgot genetics. I've had a well developed chest since I was 16 years old and a buck forty, doing only pushups at the time. My chest grows on everything, and nothing. I can't move a lot of weight, but people probably think I can.
I do have trouble with pullups though.
FWIW I like dumbbell presses (both flat and incline), various Hammer chest machines, and dips with proper form (angled not up and down). And a couple of sets of pushups to close out the session, usually.