Heights. Badly.
I can climb a ladder to a second story, but when I go to step off the ladder its vertigo like a motherfucker. Flying is a related problem, but it's only partially from the height. I think the rest is the utter lack of control I have as a passenger. My first flight was very bad and I can tell you for certain that as much as you pull on the tray table and the lady in front of you's hair, it does not control the plane.
Needles would be number 2. IV stuff mainly. Shots in the muscle don't really weird me out as much as anything IV.