[Keeper of Dol Guldur]

This is simple enough;

Confidence is in the middle of a teeter-totter, pride is on one end, and modesty / humbleness is on the other.

Balancing it in the middle is tricky - it swings one way or another a lot, but as long as neither end hits the ground, things should be okay.

You'll have to forgive my elementary school playground description for it, but it was the simplest thing I could think of off the top of my head. Possibly over-simple. But, it works.