So someone asked me yesterday why I keep running For The Horde. I have the achievement and I get no loot or anything from it. The answer to me was simple, I think it is fun. To be able to organize a group of miss matched people to achieve the goal is a great thing. Planning out my attacks as to make the defenders second guess what is happening to me is fun. Chanting "LOK'TAR OGAR" with people behind me as I charge into a mass of alliance is fun. Seeing those achievements pop up knowing that you were successful in what you set out to do is fun. I don't play this game for shiny lewts or achievements or any of that. I play it for fun.
Whenever I do something in this game I want to be successful at it. I'll put the work in make it happen. When I bought Wrath of the Lich King my goal was to kill the Lich King, and I have done that. Yes, I got some nice loot and some achievements and those are great extras. But that is exactly what they are. When I finish my Shadowmorne ya it will be awesome, but again just something extra. I think people forget sometimes that this is a game and it is supposed to be fun. Set your goals and know what is fun to you, and do it. Don't let people tell you what you need to do. Look at [Undergeared] they killed Festergut on 10 man this past weekend. They were told that it would be impossible to do in Blue gear. They never backed down and they did it. I wish them good luck on PP, BQ, Sindragosa, and of course the Lich King.
There doesn't have to be a reason to have fun. Just have it.