What are you afraid of whilst cycling

I read a story about somewhere in Europe (maybe spain) where there was a off road motorcycle race going on. An angry local tied some wire between a couple of trees and it ended up totally decapitating a rider or two.

I know its super unlikely to ever happen, but when riding in woods where riff raff kids hang out it is easy to be concerned over potential sabotaging they may have done. I mean, kids like this happily drop concrete slabs over motorways.

Its happening;

http://www.lfgss.com/thread87429.html#post2942582