Linden Lab often takes a lot of heat in the comment thread on their blog posts. Yes, both the client and the server are not at a level of stability where we want them to be. There have been painful times when a server deploy introduced a problem that made the server a lot less stable. (That blog post describes what was a very long Friday for me and a few other people....)
I think that EVE Online has really managed to take the cake, though, by rolling out a new client version that deletes a crucial boot file on Windows such that if you installed the update before the problem was found, you would not be able to boot your computer at all after that.
I think the only word that truly captures that is "oops".