This is an expert from a Gmail Blog Post re: the recent gmail outage:
Unexpected side effects of some new code that tries to keep data geographically close to its owner caused another data center in Europe to become overloaded, and that caused cascading problems from one data center to another. It took us about an hour to get it all back under control.
This sounds exactly like the types of bugs I create. The fact that Google makes these sorts of mistakes, even though they do a lot more testing and have bigger teams, etc; makes me feel good about my programming skills.