What are friendship meant to be

I thought best friend is suppose to keep in touch closely
I thought best friend is suppose to share with you every thing
I thought best friend will keep in touch with you no matter how busy their life is, no matter how happening their new life is.
but I'm wrong.
We don't chat with each other anymore for months and I can see her life is busy and happenning.
until one day I can't stand anymore, I texted her
I was like, hey, how are you, its been awhile since we last contacted.
Then she was like, hey im fine, oh ya, i have not update you rite?
Sorry to say that, that's hurt lol
Have not update me? what are friends suppose to be? and you even said we are best friend?

Now I know, we are only a friends where take pictures when we meet, upload in fb/instagram and caption written BFF~. That's all, really oh I see.

and my another good friend told me this: Friends are always come and go. I should not take it so seriously. It's true. very true.