Sometimes it is true that you need to experience a terrible loss before you can find the necessary strength to go to the next level.
Last season, Bayern came in 2nd in their league, FA Cup equivalent, AND the UCL. The UCL Finals loss to Chelsea was especially painful I'm sure, given that they were playing in their our home ground, AND were the dominant force who were expected to wipe Chelsea out.
And look what they've achieved this season. Having won the league with 6 games to spare, in the finals of the DFB Pokal (FA Cup equivalent), and now a 4-0 first leg lead in the semi-finals of the UCL.
Lesser teams could disappear into oblivion. But just like Manchester United, they have that "We will never die" spirit.
In 1999 we won the treble. Having scored 2 goals in the extra time to win the UCL over Bayern, that could have crushed them to bits too. But instead they came back strong to win the UCL 2 years later.
This type of winning mentality is why I love such teams and why I love Manchester United.