Learning new terrain is always fun. For instance, the chimney in Goldshire provides LoS to people on the ground in the center of it, on the edge you can attack. Horde was attacking the area with 2 healing priests, shadow priest, hunter, warrior, and a monk, and I just rained down HECK and ducked back into LoS when they turned on me. I died many times though, as I really had no group nor heals for most of it.
Fighting in buildings or towers is hell on LoS though.
I also learned that you phase from inside the gates of Stormwind, and the outside. So you can see horde outside the gates, for instance, but take 2 steps back and it’s like they aren’t even there.