It's too sad when you had a best friend but then you can't get with him or her anymore.
You two lost your communication and your friendship.
But maybe you're lucky, and you got his or her new phone number and start talking, he or she promises you, and you to her or him that you going to be best friends again, or that you are at least going to try.
But when you keep talking, and all your conversations are just a hi and how are you.