There are certain levels that are so fun its always sad to move on.

Level 57-61 boosting in Ramps comes to mind. Its so fun yet seems to only last 20 seconds then its on to boring Mana Tombs.

When questing its the 77-80 in Icecrown that I love, that goes by very quickly too. Still faster to RaF boost in HoL but not fun as questing for those 3 levels.