There is a difference between being an acquaintance and being a friend. An acquaintance is someone whose name you know, who you see every now and then, who you probably have something in common with and who you feel comfortable around. It's a person that you can invite to your home and share things with. But they are people who you don't share your life with, whose actions sometimes you don't understand because you don't know enough about them.
On the other hand, a friend is someone you love. Not that you are "in love" with them, but you care about them and you think about them when they are not there. The people you are reminded of when you see something they might like, and you know this because you know them so well. They are the people whose pictures you have and whose faces are in your head regardless. Friends are the people you feel safe around because you know they care about you. They call just to see how you are doing, because a friend doesn't need an excuse. They tell you the truth, the first time, and you do the same. You know that if you have a problem, they are there to listen. Friends are the people who won't laugh at you or hurt you, and if they do hurt you they try hard to make it up to you. They are the people you love, regardless of whether you realize it. They are the people who stop you from making mistakes and help you when you do. They hold your hand. They watch you live and you watch them live and you learn from them. Your life is not the same without them.