People change and they come and go like seasons do their circles. When you admit this fact you will be reasonable enough to do things on your own, live with, love them and be happy with them while being prepared for the sudden change or the eventual change.
We find ourselves sometimes getting very similar to persons we spend most time with that's why we may be close enough because of time spent. People around you are those who have the greatest impact on your personality. Make sure to have the greatest one, it's not necessary to be with the most successful lives but they must have pure hearts.