Why the fuck do people follow you on Instagram and then unfollow you later?

Why the hell do people do that? They follow me and then unfollow me. Its driving me crazy. Like why would you follow the person of you'll unfollow them later? Instead of my followers rising, its dropping. And I follow most of the people back so I'm really confused and its annoying too.
Why the fuck do people follow you on Instagram and then unfollow you later?
Post Opinion