When I first started playing WoW one of the things that struck me most was the sense of humor written into the game experience. Every once in a while you would be questing along and something small would happen that would make you laugh hard enough that you were in danger of falling off your stool.
When in a group this was usually apparent when one of your friend's character would simply stop interacting with the game. One minute they would be running around getting quests, then next they would just be standing there.
"Um...Fiara is everything ok, did you disconnect?"
"No no, I'm just laughing at the quest giver because he is making fun of me for doing every quest in the zone...."
In Burning Crusade that sense of humor got reduced to making us do lots of "poop-quests". The NPC would have you go searching through the droppings of zone monsters looking for seeds or a lost wedding band.
The Ewwwwwe facter was fun the first time, but it got old pretty fast.
In Wrath I am happy to have found that not only is the sense of humor elivated again, they have started to introduce consequences for your blindly accepting quest after quest for no reason other than an NPC has a yellow arrow over his head.
Some of those consequences are rather dire. In the horde quest chain you actually help the Undead rebels create their New Plaque that causes disaster at the Wrath Gate.
In Grizzly Hills your blind actions help one of Arthas's minions gain a promotion, and you even get good equipment upgrades from it (yeah that made me feel just great thanks...).
Others have a smaller "ah crap, that was me" moment attached. For instance while helping infiltrate a pirate compound you end up killing the only male walrus around for the sake of making a few bars of soap, and screw up the mating rituals of the local animal population.
Little things that reflect our current attitude towards our world can be amusing reminders.
Then there are some that are just funny. Just a few days ago I rolled into Amberpine Lodge and discovered a bunch of wonderfully tasting seeds that some kind person left out for visitors. They were so yummy I downed them all!
Turns out they were some magic seeds that the Lodge needed to survive the winter with...d'oh!
Well, there is only one way to get them back.... (notice that the guard walking by dosen't even bat an eye.)
40 years old, and somehow this is still funny.
Oh, and the best part is that the outhouse is re-usable after the quest is done if you ever need a cheap laugh.