I liked the idea of circles. I'm part of multiple social circles and what might be interesting for one could very well be meaningless for another circle.
I also liked YouTube chat. I had Messenger at the time, but I could contact my family on YouTube chat too. So I deleted my Facebook account and switched to chatting over YouTube. Then they shut it down, so I just let it be and stopped talking with my family.
The "circles" were awesome. It was a breeze to tweak your feed based on which circle you put someone in. Rather than get all the posts from a very hit or miss account I could pretty much say "only the top posts".