I don't really know how to define it but I think I have a phobia of Rapid Motion, be it in any form. Whenever there's sudden, jerky motion, I start to all panic up, even though I know its safe (easiest example, on rides with a safety harness). Dunno why, and hate it too... makes me sit out on most of the rides when my friends are up there! Also, while driving, some of the craziest overtakes freak me out (when I'm not driving and sitting alongside! :P) but I don't think I can ever drive crazily like that... fast I can go, quite fast, but not drive that way when the car changes its direction completely in a split second.
Also recently (like 3-4 months) I've been afraid / have a phobia of fainting. Yeah that's right, weird, but true. Whenever I used to feel a certain symptom relating to fainting or something, I used to panic, and then actually started feeling more symptoms (read: Panic attacks). Made life hell for a while believe me, couldn't consider myself worth for doing any responsible thing. Thankfully been fighting it for a while and its getting much better to control myself now!