I assume I'm below average
I doubt Derek really believes this.  At least for me it would be paralyzing to think that I was below average at everything.I assume what he really means is, "below average in x, but I make up for that with y."I think it'd be hard to have done as well as Derek if you honestly managed to convince yourself that you were below average intelligence, below average skill in your profession, below average ability to motivate yourself and so on.  It sounds like he's setting the y to "in being humble and willing to learn from others".Otherwise why would you try anything hard if you believed it to just be a lottery with bad odds?  Wouldn't it be better to leave it as an open question so that you're self critical and are able to suss out your own weaknesses?