Contact.

Saw a friend on a subway platform. I was in a train going one way, and she was waiting for the train headed back from where I came. After the doors closed, I felt so stupid for not getting off. I was just going home, and therefore didn't have any kind of schedule to keep. She was going to work, but a few minutes just to say hi and take care would have been a good thing. Can't let laziness get in the way of contact. That's how people disappear. One of the ways.