I'm having a whale of a time with Guild Wars 2, but I am playing it pretty much on my own due to problems with the grouping/instancing/server overflow system. As half the world pointed out on my piece yesterday, in theory if your party is rendered disparate by the game you can right-click on party members and select 'join' to be dispatched to whichever overflow shard your chums are on, but only in theory. It doesn't work much of the time, and to the point that me and mine simply don't bother to even try it now, especially as we knew that even if it did work we'd soon be torn asunder again should we have the temerity to change zone or embark on personal quests.
Turns out it is at least partially a bug rather than the design flaw I accused of it being, ArenaNet having been in touch with the following statement, and promise that they're working their hindquarters off to improve the situation.
“We currently have a couple serious bugs with one of our important back end systems. This error is causing the loss of trading post, players to sometimes be separated and unable to travel to each other when switching maps and entering overflow servers, and numerous guild errors. We are very sorry for this inconvenience and are currently working around the clock to try and remedy this error.”
“When this bug is fixed overflow servers will keep parties together and players will be able to travel to the same overflow server as any friend or guild member who is in an overflow.”
So there you go. I've double-checked, and the bug is also what causes groups to be split up if one player enters one of the instances for their personal quest. There is no in-game explanation or elaboration on what's supposed to happen or why groups get split up, so if you've been affected by it, now you know why. It is a very, very unfortunate problem for an MMO to launch with, but it's a relief to hear it's by accident rather than design.
With the game now on general release, as opposed to just the three-day early access, the servers are going to be even more flooded, and thus the issue even more acute as folk are scattered across the overflow servers. Let's hope it's resolved soon, and is priority number one, above and beyond the payment systems.