What is the difference between confidence and over confidence? | HR Interview Questions for freshers

A complete knowledge about something gives confidence. But over confidence is where we actually forget our capability and get into problem.
"I believe that I can achieve the Goal" shows confidence.
"Only I can achieve the goal" shows over confidence.
Confidence may land up in failure sometimes, but will achieve greater heights.
Over confidence may result in success sometimes, but will surely pull us down.