Favre's curse is that he cannot let go of a grudge. Mainly against Thompson, not so much against Rodgers. The question he was asked in the interview was a great opportunity to put it all behind him, but he couldn't bring himself to do it. He could have said, "I'm happy for them. I was hoping they would win it". But instead he gave a rambling answer that most, rightly or wrongly, saw as a veiled shot at Rodgers. If the Packers win the Super Bowl this year, Favre needs to do 4 things:

Call Aaron Rodgers and congratulate him.
Call Ted Thompson and congratulate him.
Call Mike McCarthy and congratulate him.
Give an interview in which he says he's happy for the Packers and their fans.

That's what he needs to do. I'm not sure he can bring himself to do it though.