An ESPN artilce suggests Brett might not be done after all. 

With his family "tugging" on him to play, Brett Favre has an "itch" to come out of retirement and report to training camp with the Green Bay Packers later this month, according to sources close to the team and player.

I guess he felt like he hadn't jerked Aaron Rodgers around enough.  Favre was a great player, a great competitor, and on the field he's as likeable as any guy in the league, but he's been one huge dick of a mentor.