Quote Originally Posted by Jojoya View Post

Playing through Icecrown during Wrath of the Lich King absolutely sucked due to phasing. You couldn't help friends unless you were both on the same quest. You couldn't help friends if had completed the quest already. There were multiple other phasing issues in WoW even after that ("sorry you feel to your death as we crossed over a zone where we weren't on the the same phase"). They did some tweaking on the worst of the problems but still it was generally a poor experience when what you can see and what your friends can see are 2 different things.
Don't forget "can't help summon the raid because phasing".

It got better later but Icecrown was terrible.