Google Wave team has done a survey regarding what people like in Google Wave and What not. Team has just shared the results with the world. The top of the list in liking is 'The concept of Wave'. Most of the users of Google Wave didn't used the collaboration tool before so they were simply amazed at the power of the wave. That's why people also liked 'Ability to Collaborate' more. Here is the liking graph.

Among the dislikes or issues (thats what Google calls it), People actually didn't liked their loneliness. They voted more for "My Friend/Contacts don't have an account" under issue. Google Wave is invitation only so people who got invites share them with their friends and families. This is a slow process which actually paves the way for dislikeness. If you still don't own the account and waiting for one, well drop in your email address and contact at Google Wave Invite. People actually voted for "Its too slow" as the second worst thing. Personally, I feel this is not the case but the ability to catch up with the wave might bring people towards this opinion. See the issues graph.