Code as if the next guy to maintain your code is a homicidal maniac who knows where you live.
The secret to building great products is not creating awesome features, it's to make your users awesome.
In many cases, the more you try to compete, the less competitive you actually are.
Just make people better at something they want to be better at.
Make the right things easy and the wrong things hard to do.
Twitter, for all its good, is a hate amplifier.