The one I liked the most was Google Plus. There were a lot of naysayers, and still are, but Google+ brought a refreshing take on a social stream, Circles was a beautiful interaction at the time, and its focus on Photos won me over. Though I always saw it for what I think it is, a new unified approach to a Google Identity, one that began to unify all its products. I for one don't mind it, but I know I speak as a fanboy. Still a G+ fan, and use it regularly.