Because it is all about Brett.
At New York, he demanded (and received) his own separate locker room, instead of sharing a locker room with the rest of the offense.
He was always going to return to the Vikings and played out this whole "Will he or won't he" thing to receive the largest amount of media attention.
And then there are the reasons why he wanted to join the Vikings. Because the Packers didn't want to go through the "will he or won't he" thing for the third time and give Rodgers a shot, he felt disrespected. So the best way to get back at Ted Thompson and co (according to Lord Favre) is to beat them while playing for the Vikings.
In regards to you believing he is at the middle of the bell curve of QBs, you are wrong. He is bottom 10. Easily. For the Vikings to pay him $12 million for a year (he did sign a 2 year contract though) is ridiculous.
If I were a Vikings fan, I would be pissed off. My team could have paid someone like Jeff Garcia half of that and then went out and got another decent receiver.
Favre's legacy will no longer be the Packers QB who loved to "sling it and have fun", he will from now on be forever known as the guy who holds the record for most intercepts, mooned the team that gave him so much and took the entire league and fans for a ride.
