If you follow many software or computer science related blogs you may have already seen the article linked below. I’m going to link to it again anyway because everyone who is involved in software should read it.
Extra, Extra – Read All About It: Nearly All Binary Searches and Mergesorts are Broken
The general lesson that I take away from this bug is humility: It is hard to write even the smallest piece of code correctly, and our whole world runs on big, complex pieces of code.