Quitting.

He feel like a failure. You're not good enough.

There are many definitions for the word 'quitting':

To stop, cease, or discontinue.

To depart from; leave (a place or person).

To give up or resign; let go; relinquish.

To release one's hold of (something grasped).

To free or rid (oneself): to quit oneself of doubts.

Sometimes quitting is a good thing. The question is...

What is a good thing...?