Oh yes, it's great that my countless hours of planning were undone by horrible luck that made absolutely no sense. The team that beat me wasn't even paying attention and set out the lineup they did by accident, but if you think that they deserved to win by doing that, then that's your opinion.
I don't agree that I went into the game cocky. I carefully selected a lineup that would be good enough to win even if the other team used one of their better lineups, and the box score suggests that I did that correctly. My main mistake was not scouring the transfer list for an extra player or two in order to provide better depth in my lineup in the (very unlikely) event that my opponent would make a push for a close game. I also could have tuned my lineup settings in a slightly better way, as I had planned my minutes for blowout conditions. Those are two things that I could have done better, so the loss is my fault, but I'm fed up that I have to keep worrying about preventing disasters that shouldn't happen in the first place. I'll add that it wouldn't have made sense for me to use all of my best players in a game like this; resource management is an important part of this game, and weekly minutes (for game shape purposes) have to be planned out every week.
Anyway, I don't really care about this game anymore, and it's not just from the one loss in the cup. I've had several very close losses this season that were extremely frustrating, before my "meltdown" on the forums. If working really hard to do the best I can do is only making me angry (due to bad luck that I can't control), then what's the point of putting the time in?
You are welcome to your opinion, but that's how I feel about the game now.