Wrath is the only expansion to date that made me quit for over a year. Just hated the theme, the wc3 stuff, Arthas here Arthas there. It never appealed to me. I found MoP lore to be the best. I perceived it as much more subtle and mature. The Arthas tragic-hero thing never did it for me.
Coincidentally my friends stopped playing in Wrath as they didn't like it and thus I was left stranded in Dalaran with LFD and **** all.