Why does the better team lose major footfall finals?

After watching the champions league final between Chelsea and Bayern a thought struck me this is another final where the better team lost.

Is it because the wight of expectation is on the better team who then proceed to play their heart out for 80+ mins only to fall at the final hurdle when the opposition somehow gets themselves back into the game.

Is it because the weaker team has nothing to lose so they can put it all on the line knowing that no one expects them to lose.

I suspect its a combination of expectation, how much energy they have had to expend in getting to the final and throughout the season and also a certain sense of complacency. People believe football like life is inherently fair. That the better team/person wins the cup/gets the job/ secures the promotion but that is not usually the case. Normally all these things can hinge on something as innocuous as sloppy penalty, being in the right place at the right time, who you know not what you know or just plain dumb luck.

As humans we are programmed to search for meaning in the meaningless but at the end of the day you just have to say trying to predict football is like trying to predict life. It is not going to happen so why not just go with the flow and enjoy the ride while you can.