I think IF397 makes a very good point (for once
), If we thought that rides were perfectly safe and that accidents never happened, then rides would induce less fear. I suppose there is a certain amount of fear instilled by the fact that you are travelling at 60mph past huge metal poles, but if rides were perfectly safe then we would know that nothing was ever going to go wrong and coasters would just be a train that was pointless because you end up in the same place you start
I also suppose this is why people tend to prefer taller faster rides, as they would appear to be more dangerous. I don't think rides would be boring if they were perfectly safe, but I think that the thrill would be a different one, if there was still a thrill at all.