Good morning, Jesser.
I see in this dream a further sense of outgrowing acquaintances and certain relationships.
You have decided that you don't want constant conflict and criticism - thus you leave when the teacher yells at you. You've left this teacher behind - you have nothing further to learn from such abuse.
Your "friends" leave you behind in the store, and you get ridiculed for that - perhaps it is perceived that they are maturing faster than you. But, when you find your old haircut in Sara's bathroom, you find that it no longer pleases you - so perhaps it is you who has changed, just at a different rate and in different ways than the people around you. While they show little perseverance, you do not want to move on until you have found exactly what you want.