I am scared of them. There's this one in West Edmonton Mall, the local shopping mall, called the mindbender:
I wouldn't go on it.
But I did go on the Twilight Zone Tower of Terror in Disneyland because it reminded me of Bioshock. Damn was I glad I did. Easily one of my favourite rides.
Same goes for California Screamin'. I didn't think I'd go on it, but my dad said he would, too. So we tried it. It was very fun, and you didn't even notice the loop-de-loop.
That's what I'm most afraid of. Loops. What if it gets stuck upside down? No thanks. Oh god, no thanks. Also, I wouldn't go on a roller coaster made of wood or where you're hanging.