If Icould change one thing about myself, what would it be?

I want to change everything myself. However, it is impossible to change all of me. One thing that I want to change is guessing something. I cannot see or think without guessing. When I talk with someone, I always guess what they think and feeling during a talk with me. I worried to think how I look from other people. When I talk with one of my best friends, she points out about I am too much thinking. I often have mistakes, because I do action though my thoughts. I need a long time to think hard if a problem is serious. I should think something simply more than now. If I solve the problem, this is a step up of my growing.