I love the "we can do better" attitude through the post. Imagine if all developers had this mindset! Of course if we all did, then nothing would ever get done because we could always do better. Sometimes you need someone to say "this is good enough".
Ha! You're right that it can be a hard balance.
I think it's easier to stay on the "we can do better" track when working on a hobby project like this. At work I'm typically thinking about whether a marginal day spent polishing something is worth more than all the other stuff that we want to do.
But with Flappy Dird I knew that I wanted to push until I was either happy with the project or didn't believe that I could push the game any more.