I'm mixed. When I entered today with my Horde lv62 druid to run through the Halloween event quests, zombies and zombified players ruined the fun. Then again, when I entered the game with my lv16 Alliance warlock, I had the time of my life. And in Friday I had a blast running Stockades as a zombie with my lv45 warrior and my brother. Absolutely hilarious session with loads of 'BRRRAAIIINS'-shouting and fury.
This difference in experience got me thinking the reason.
It's all about expectations. About the activity you are about to engage with. About the fun you are about to experience. About the entertainment. If these expectations are not met, but are altered in a way the player cannot change, the reality doesn't conform with the expectations and most probably the overall experience is ruined. If you go to a movie to see a light comedy and end up watching Coen brothers' "Fargo", I bet you are not going to be very happy. Fargo is a great movie, but it isn't exactly light comedy.
I loved to play as zombie on my lv16 toon, because there were other people engaging in the similar activity. It was a bliss, and I could easily get away from it. My expectations were different with my horde toon. I expected to be able to do the Halloween quests -for the achievements, I admit- but was denied of the fun. With the Ally warrior I expected to be running as a zombie and eating brains, and it was hilarious.
This can be taken a step further. Players are like any consumers in that they are ready to tell different things in surveys than what they really want. AoC was marketed as a completely different experience than WoW, and players were jumping in joy. In the end, it proved to be too different, causing the game to be next to abandoned (yea, yea, nevermind the technical issues etc. It's a simplifying example, ok?). War didn't even try to change the mechanics, but made the change in the way the game was played. And was very much easier to digest.
We are slaves to our expectations. When they are not met in full, we feel cheated.
But I also came into a conclusion with the world event. I just love the unexpectedness of them. Nevermind the fact that the Invasion is in fact aimed for the bored level capped people: I couldn't touch the Lich Kings stormtroopers with the Druid (well, I could but not solo). Never the less, I had fun with the fact that everything had to be taken as it came.
I'm off to see if I can contribute in the Ally side. CHARGE!!!