One can examine this rule particularly in the light of the Super Bowl. Take last year, for example, and Super bowl 42, where the undefeated Patriots were overwhelming favourites to overcome the giants. The game saw the Patriots lose their perfect season record to the universal underdogs.
Also, do not become overly fixated by talk about the
nfl games previous seasons and related statistics. Many fans are liable to do this, and it can be detrimental in terms of ascertaining odds.
Do not be a slave to last year's stats, as they are unlikely to be repeated. Look especially at the players and the lines-particularly important in college football, where the lines on each team vary hugely from year to year due to the fact that the teams change when graduates leave.