Control: QBs give the most amount of control over their own point production, even though  matchups matter more than most people think. 

Attitude: Don't trick yourself into thinking that QBs are that much more predictable than D/ST. Ramdom scatter is large from QB, which might not be intuitive since the average score is also highest among fantasy positions. Since the QB error is wide if you have a choice at QB, hedge against a possible bust.

Numbers: The average QB score is around 17 points, with uncontrollable error around +/-8. Low teens are normal, but you are justified to feel unlucky about single digits.