Classic: didnt play
Cata: it finally ended
Mists: Its so damn beautiful
Check out my Character Bio please http://www.mmo-champion.com/threads/...-Aegus-Shawson
I'll leave out lore since no one seems to care.
~Vanilla: COLORS! No other MMO of its time had colors like this. I was completely taken.
~BC: Gear design and dungeons. Love and miss these.
~Wrath: Addition of achievements and Ulduar. Yeah, it was that good. Still try to run it weekly.
~Cata: New zones. The quest flows are almost too good in them. Plus LFR.
~Mists: Most of it, so far. Account achievements and mounts, pet battles, pandaren and even the new class is damn good.
BC: Illidan (man I wish that I could raid back then). He was my favourite character from WC III.
WotLK: Actually being able to raid properly (only ICC towards the end though) and this one piece of music: http://goo.gl/UdwmT
Cata: Old world revamp
MoP: Being part of some 'new lore'. Most of the other expansions have had some other history towards what we were trying to achieve within the game. Now it's all about being part of the evolution I feel.
-- To troll or not to troll? --
BC - Nagrand
WotLK - Story
Cata - Revamping of old zones
MoP - Account-wide achievements, mounts & pets
BC: Netherwing Drakes, and Nether Rays,
WotLK: Ulduar, and Ulduar style hard modes, plus Death Knights.
Cataclysm: Raid Finder, even though I'm not a fan of it, Transmog, and graphic rework of Azeroth zones.
Pandaria: Monks, Pandas, new Talent Tree system, Pet Battles, and account wide achievements/mounts/pets.
Hard to pick just one best thing from each expansion so I'm going with a couple of 3-way ties here...
BC - Outland zones (coolest looking zones in the game imo), flying mounts, and some of the best world PvP ever (Hellfire Peninsula and Isle).
Wrath - achievements, zones (second best looking zones in the game imo), and closure to the Arthas/Scourge story.
Cataclysm - old world redesign, LFR, and transmogging.
Can't say anything about MoP because I don't have it yet. So right now I'm just going to say the best thing about MoP is the fact that we'll eventually get to kill off Garrosh for good.
TBC: The raidmodel
WotLK: The leveling experience
Cataclysm: The instance difficulty at the start of the expansion
MoP: Not playing, so wouldn't know
TBC: Simply amazing raid content, attunement heavy raiding hell yea =)
WotLK: Duall spec, this was such a pain before
Cata: Guild leveling system, i thought it rocked.
MoP: ......... ?
negative's coz i feel like it
TBC: Flying / arena's / heroic system / 25m raids / Badge system (later to be known as emblems/JP/VP)
WotLK: no more attunements / LFD / ToC < haha ^^
Cata: LFR / Lack of content ;p
Classic: brand new game, 40 man raids, AQ gates opening event.....being almost 8 years younger and actually having time to play.
BC: raid model, having to work for attunements, 25 man raiding dominating
LK: ulduar hard-mode model, nicely done world, did not like it after toc was putinto game.
CATA: did not like at all, basically skipped this expansion
Pandaria: just bought yesterday, still checking it out.
Burning Crusade : Flying Mount
Wotlk : Ulduar
Cata : RBG / Transmog
Mop : Monk / Achiv account wide and pet battle