I do this as well. I wish I didn't but I can't help it. I don't know who I am or who I want to be so I act and be who I think others want me to be in any given situation. I've gone as far as "changing" my likes and dislikes depending on who I'm around with the thought that they will like me/accept me better if I like what they like and act like I think they want me to act.