Back when I was writing up the five must-do Horde zones and five must-do Alliance zones articles, I decided to play through those zones again just for experience's sake. In beta and the early days of Cataclysm, I spent a lot of time going through the Alliance 1-to-60 leveling zones and experiencing the content. I remember being really pleased with how well the zones were laid out and how nice it was to see actual story instead of just, "I'd like six pig heads; go get them from the field next door." After that experience, I played through them on Horde side and was terribly pleased to see they were just as well done on the other side of the faction fence.
I didn't really think about it afterwards, and it wasn't until I decided to do these two articles that I took it upon myself to level through these zones again. And this time ... something had changed, a little. Perhaps it was because it had been so long since I'd played through the Alliance zones. Perhaps it was because I had just finished experiencing the Horde zones when I went back to Alliance. But there was something very, very different about the experience.
While leveling as Horde, I was having all kinds of lighthearted fun mixed with bits of serious story. While leveling as Alliance, I felt like there was an oppressive weight bearing down on me at all times, and that weight was never really removed. Odd, that.