#1 Quite simply, Valencia wanted it more
Barcelona are one of the most decorated clubs in history and the current crop of players are no strangers to winning, having won almost everything winnable in the game.
Most of the players have been the core of the Blaugrana side which has been utterly dominant in the last decade and came into the fixture as defending La Liga champions, while they had also won the Copa del Rey in each of the previous four seasons consecutively.
By contrast, virtually all the Valencia players have won next to nothing and are nowhere near being the global superstars that their Barcelona counterparts are, while the club itself had been without any form of silverware for 11 years.
This was evident in the game, as the Valencia players showed an extra drive and hunger to win the trophy, throwing themselves into tackles and putting their bodies on the line, while defending resolutely to protect their lead.
It is hard to keep yourself motivated to go the extra mile having won so much, and this must have played in the psychology of the Barcelona players, as they did not exert themselves as much as the Valencia players did and this played a role in denying them of their 31st Copa del Rey trophy.