Aura Colors and Meaning

Hello! So, over the past year I've picked up on several people's auras on random occasions. I was wondering if anyone knows what they mean.

Deep murky black/purple/pinkish: this guy had some serious ego issues and I suspected he was a sadistic narcissist (powerful too). He was running a work training session in which he made put people to fear and made them cry during off hours.

Bright red: this lady is insecure, yet pushy. At the time she was trying to push her own occupation on me for the sake of satisfying herself.

Green: random person in a parking lot and also my sensei during qi gong

White/silver: an onlooker who was listening to a conversation between me and a deep soul connection. We were talking about the universe and how it may just be an illusion. And also some stuff about the Sun's orbit around the Galactic Center.

What do you think? Anyone have insight into the meaning behind aura colors or the reason why they change?