There's no such thing as too confident.
New levels of confidence just open up your horizons to things you never thought possible.
It's a belief in yourself and your abilities and when you have it, it's great. You can't tell yourself to 'have more' or 'have less' of it.
When I have confidence, I can only fake not having it. When I lack it, I can only fake having it. Neither fake is convincing.
The other day I introduced myself to this cute little asian girl at a restaurant I was at because I saw her looking at me a few times. I would've _never_ done that before, but for whatever reason, I just had the inner strength to do it without hesitation.