Friends

I have a deep question abt friendship that i cannot understand. What are friendships actually? I always thot friendships are abt shared lives. It abt having both parties to share, to enjoy activities, to trust, to rely on. So if as a friend, we don't share, we don't do activities together, are we still friends? This is a very high school topic. But i realised it plagued me big time. I guess different ppl hv diff perception abt friendship, so does tt mean i need to change? But why is it that i need to change my understanding to suit the other and not the other to suit me? I had to adjust to the other party just cos the person doesnt like to share, instead of her trying to share more so that i can be involved in her life? It's kinda funny. I no longer know what friendship is. And perhaps friends are not impt to me anymore....It has to come to this point.