I work in the largest, busiest Theme Park in the UK. The amount of stupidity from guests is frankly astronomical, some of my favourite examples:

Not knowing how Velcro works
Thinking a phone can survive a 30ft drop at 40mph
Thinking we haven't spotted them filming on their phone against the rules

And of course:

Has anyone died on this?


And then there are the ride geeks. *shudders* Why anyone would want to try and stroke parts of the track/cars, I have no idea...