Do you ever stop liking someone? If you do, you could take a look at why.

Do you know why those people decided to walk out?

There have been times where I stopped communicating with someone, or vice versa. On my end it wasn't usually that I was mad at the person or something bad happened. Most of the time, somehow I just stopped wanting to pick up the phone, or write the email, as compared to someone else I could contact at that time, something else I could do.