Interesting discussion. I think Top 25 Leaks is absolutely right about the effects of hormones. And I've observed several examples of some of what's been discussed here.
But at the same time, there's also no question that in many cases the negative effects (in terms of distraction, loss of focus and/or intensity, etc.) outweigh the positives (in terms of outlook on life, desire to impress, etc.). I've seen plenty of examples of that too.