How friends become strangers?

People whom I loved the most have now made me to see them as strangers.
Is it the time which changes everything?  Or is it the new bunch of people?
I stood like a calm tree waiting for them to come and finally when they did, we met like strangers. The aura was oozing coldness.
I could never believe that my best friend who was my main would in that very spur of the moment.
I miss the days spent together and I miss us.
If this is what you have become then i would still like to have friendship with this well known old stranger.