Write comments like you’re talking to a rubber duck!
Good comments take care of 99% of what you hand over and — more importantly — take care of your documentation. Your code should be the documentation.
Comments are also an excellent way to show off. Ever wanted to tell someone how awesome a bit of your code is but never found the chance? This is that chance! Explain how clever it is, and just wait for people to read it.
Egos aside, though, comments do force you to write nicer code. I’ve found that writing extensive comments has made me a better developer. I write cleaner code, because writing comments reminds me that I’m intending for others to read the code