Just because you've "met" 500 people it doesn't make you a "friend" of them...

If someone showed you just pictures of 400 of them without their names and asked you to name them and tell their age, location, hobbies etc, partner/boyfriend is etc (which a "friend" would know) you probably wouldn't be able to do it.

They aren't "friends" they are just contacts. Nothing more.
Peeps that you've had contact with at some point.

I often got people who were friends of friends wanting to friend me and I had absolutely no idea who they were.

It's all bullshit really.