Guess what caused a serious outage of a system at a customer that I know, with an estimated impact on his bottom line in the seven-digit area? Yeah, right: naiv

Guess what caused a serious outage of a system at a customer that I know, with an estimated impact on his bottom line in the seven-digit area? Yeah, right: naive copying of some XML out of IE into the configuration of said system. Including those '+' characters, which resulted in it not exactly being XML anymore.