Basically, if you accept that your first 10 games will suck, and you don't try to make your first game fantastic, then your first 10 games will suck. Worse, you might get good at developing sucky games. For most developers, not just game developers, it's likely that their first some number of projects will suck.

I always thought that the mantra about your first 10 games will suck was a way to take the pressure off you and get you to develop a game. The problem is that we psych ourselves out; we don't develop anything because we're too fearful about making a bad game, and we procrastinate, and we hem and haw and never develop anything.