People going to Instagram to escape their existing Facebook connections. Starting a new graph on Instagram that is restricted to their current and more private interests. What I've observed.
People do it within Instagram even, known as "finstagrams":
>Finstagram (Finsta) is student's fake (or second) Instagram account. Students, usually girls, get a second Instagram account along with their real Instagrams (Rinstagrams), to post silly pictures or videos.
Exactly this. In facebook I am friends with everyone I know from high school. It feels depressing to go on facebook nowadays, because it's just littered with political vomit and rehashed memes. In Instagram I follow only my current high school friends, and generally people that have cool lives. Going on instagram feels much better.