As a developer, 2 and 3 are basicly feedback. If you check in hurry and no one ever tells you it caused a problem, you will slowly unconsciously start believing yourself a god. I never cause a problem with this!

Except I do. And as with anything, feedback takes you back to reality.

Plus you learn where you tend to make mistakes and thus have a chance to study a bit more about area to learn how to not make mistakes.