Lazy developers throw exceptions, good developers return errors. Exceptions should be exceptional.

I'll use URL to this bug in my next comment-holywars to prove this point.

Yes, it takes much less code to throw an exception in hope some code will catch it, but while compiler (not runtime) doesn't check it - this technique is not safe. So we should return errors, check them and handle - sometimes it means returning error further, but in some function we'll write code to handle this case without crashing the system (or, at least, it will shutdown everything gently, without panicking).