I am in a football pool at work (which isn't for money, just bragging rights) where you just pick the winners each week. I went 10-6 for opening weekend. Not bad.
But then I figured it out that another teacher just picked all home teams--straight home teams--and went 10-6 as well.
Home field advantage. It is amazing how, statistically, the home team wins more than 60% of the time.