Good idea, bad execution
Real name policy - people didn't want their social stuff on Google searches, they should have isolated everything to its own domain
Merging accounts - people used to love having multiple YouTube accounts and Gmail accounts, with G+ came the one account policy and people hated it
Wonky social concepts - They should have just stuck with the basics people knew, "friending" and "following" with an easier restriction interface
G was one of the few that could have succeeded against FB but they fok up, I blame mister monkey