This has been a good discussion, thanks to you all. Perhaps I can add a couple thoughts that may be relevant:
1. I tell my pitchers that 'damage control' is important. The ERA does tell us something, but the amount of unearned runs also tells us a lot. The best pitchers are great at damage control and thus allow very few unearned runs. The amount of unearned runs is a stat that the pitchers and I talk about.
2. This is important in every day life as well as in baseball, and teaching it to young children/athletes is important........control your emotions; don't let your emotions control you.