Why don't i play Alliance? Well, when I first started playing (shortly after TBC release), I rolled an Alliance toon, a Dwarf hunter if I remember correctly. This was on the Lightnings Blade(EU) server. What I found was that, for the most part, all the Alliance players were young teenagers. As a 27 year old (at the time), that made for an unpleasant and uncomfortable social experience, mainly as I have little in common with young teenagers. I almost gave up on the game round about then, but decided to give the Horde side a chance, and I'm glad I did. To answer the question, I don't play Alliance because the playerbase on that side of the game, in my experience, tend to be immature teenagers, whereas the grown ups seem to favour the Horde side. I guess that maybe comes down to the perception that the Alliance are the "Good Guys", and that'll always seem more attractive to kids.