I fucking despise them for three reasons;
1) In matches where I should be neutral, I side with the underdogs almost every time. Obviously, Spain are not the underdogs, so yeah.
2) Their boring ass play style. I'm fed up of people just rimming Spains asshole for managing to pass the ball from left back to center back to left back over and over and over and over. Yes, it's successful, but how is it entertaining? It's way more entertaining to see a defensive team utilize cold blooded tactics to their fullest extent. With Spain it's just Xavi passing to Puyol who passes to Pique who passes to Xavi... Repeat 200 times.
3) Their players are a bunch of fucking assholes. You've got Ramos, who I'm sure is going to try and murder someone again before this tournament ends (although his partner in crime Pepe isn't next to him, so he might have to put in a bit more effort), and the rest of the team, who are a bunch of diving fuckwads.
Now, previously I said repeat passing from CB to LB 200 times. This would actually be 400 times, but Spain spend so much friggin time rolling around on the ground while the few players that can resist doing the same swarm the referee that it's practically half the match. Star struck (or corrupt, it's the UEFA so I wouldn't be surprised) referees actually buy into this shit and thus year in year out you get treated to Spain and Spanish league teams winning competitions by bullshitting their way through. Nothing gets me raging more than thinking of all those unjustified fucking penalties and red cards that have helped Spain along their way.
Then theres stuff like dancing around a member of the losing team taunting them after a match, which is just plain disrespectful. So yeah. They're a bunch of cunts.
EDIT: Also, never forget. Coughing at a member of the Spanish national team = red card, 50 match ban, 2 year prison sentence.