Who are my close friends?

Just some add up from the previous post about social media influence. I didn't create any close friend list at Instagram yet.

How should I define close? Who should I put in my list? 

Sometimes I (I believe not only me) find it very surprising to appear in someone's close friend list! I know I should feel honoured, but it's like... "Wow we close? For real?" I don't know whether is it me being too pessimistic towards how others position me, or I instinctively refuse to be close with them? 

P.S.

Surprisingly (er I don't know why I find this surprising), my boyfriend, my other half, is my top one close friend. :3 Not an easy task mate, I hope you survive.