Your friends are a reflection of you. The way they think; the way they act all have a basis from within you. You do not truly recognize who they are until you recognize who you are. When you love and adore a quality in another, it is a reflection of something within yourself as well as those qualities you abhor in another. That, too, is a reflection of you somewhere. Deep down perhaps but it can only be reflected as the things you notice are the things you know about yourself.
When you love and accept others as who they are, it reflects that you love and accept yourself as is. When you judge another, it is because they reflect back to you something you judge within yourself. You change your friends when you want to get rid of something you don’t like in them. It would be so much easier and more effective to either accept or change that aspect of yourself or you will attract it yet again in another individual.