I've fortunately never been robbed in a dark alley and that's not something that sounds like a real threat to me, but I had to intervene on nightmarish code-bases and some “convenient” feature sometime turn to be real curses (JavaScript `with` anyone?).
Edit: it's late in here, and I completely missed your point. I'm personally not usually afraid with language features, but some requires more work than others to be accustomed to, and not everyone is willing to spend their spare time doing so.
