Superstitions annoy the hell out of me.
I don't believe in any, and I think they're essentially what began as old wives' tales and were perpetuated by self-fulfilling prophecy and stuff like that. For example, the reason bad things seem to happen to people on Friday the 13th is because they expect them to. So anything that could be construed as bad is blown out of proportion because "ZOMG IT'S FRIDAY THE 13TH". I would also bet anything that I can find more examples of bad things related to, say, the number 12 than 13. It's just arbitrary to me.
The death penalty?