I dont get scared on roller coasters, ive been riding coasters since i was 3, so nothing is really too intimidating. My first ride on Nemesis when i was about 8 and actually too small (my uncle managed to sneak me on once, didnt manage it the second time though [:(]) scared me a bit before hand though.
Shot or Drop towers are way more intimidating to me, and they are the one thing that can really scare me. Dive Machines im fine, i trust B&M, they feel comfy, i can see the track in front of me, thats all good. Its going straight down when you're looking outwards that gets me for some reason.
Cliffhanger at Flamingoland first time round really scared me, now im okay. Its the build up of tension i think BEFORE falling/shooting up on a tower ride that gets me. PLUS THE NOISES all add to it, e.g the sound of compressed air tanks on S&S space shots. EEK! But i love them for the fact they still have te cpability to scare me.