Why do girls immediately walk away when they see approaching them?

Do you have a serial killer smile?  It’s similar to the rape smile but less sinister than the smile that says “i’m going to kill Batman!”

Everyone is constantly expressing the contents of their true personality - their subconscious patterns - through unintentional subtle cues.  Body language, posture, etc.

And everyone is constantly "reading" other people's cues on a subconscious level. This is what "gut-feelings" are about.

If people who do not know you are turning away, you probably have a lot of repressed anger or self-hatred and they are reading that. If they KNOW you and are turning away, it is about what they actually know about you that turns them off.

 In your case it may be that they are intentionally avoiding you. Why that is only you can and need to figure out!

Whatever it is, they're trying to avoid it...