When I was a kid, I once waited in line for at least an hour and half to ride a roller coaster. I was excited, but also terrified. And at the last minute I chickened out.
When it was my turn, I burst into tears and totally refused to get on. I'm sure my Dad was quite pleased, after waiting all that time.
So, yeah, roller coasters freak me out. Even videos of roller coasters freak me out. And this video of the world's largest giga coaster in North Carolina, from a rider's point of view, kind of makes me want to throw up.