why do we lose friends

There days it takes a lot to keep friends. People are so busy with their own lives. It takes a real effort on every ones part to stay in touch. Personally, I tried with a lot of people, but often it was just me making all the effort. Sure they would be so glad to hear from me and we would meet up and it would be really good and then nothing. At least until the next time I made the effort. I just gave up a few years ago and have become a bit of a loner.