Nobody cares about fishing, so it gets randomly interrupted so you can stop doing it and do something else!
LoS is for noobs, which is why there is no need to care for it! You can blink inside trees and stumps and shoot people from there! You can also randomly end up in the sewers, or worse, if you blink around specific spots in Dalaran!
Westwind lift is evil, and people shouldn't use it! If they do, and they try to walk off it before it's fully down they must be punished by taking as much as damage as if they jumped from the top of it, and instantly dying of course!
Teleporting is for hackers, which is why the K3 teleport works only during the quest, and you cannot continue the quest chain until you can get there without using dirty tricks like teleports! Same thing for the Borean Tundra in the final quests of the zone. You can fight Valanaar, but only mages, pallies and people with hearthstones available can leave the area, everybody else must jump to their death because teleport stations are broken totally disabled for a reason!
Wrathgate and Battle for the Undercity are so not important, and there's a lot of phasing there which requires core knowledge, so it's best if that barely ever works so people can't do it! It's not like it's a major quest finale or anything...
Horde and Alliance can chat together in general chats, because everybody is so friendly to each other!
Mobs can follow you so much longer than Blizzard intended, but what does Blizzard know, right? Obviously it's such a great feature when the Vyrkul mobs follow you all the way to Valgarde Keep, because all they really want to do is chill with that pipe smoking draenei there and have a good time!
Everyone likes it when mobs use knockback and totally knock you out of combat, so this is present everywhere!
Big fat dragons who can run faster than sprinting rogues are also incredibly cool!