I agree everyday kindness goes along way. I don't how many times a person lets go of a door on my face or not bother to help when I'm stuggling with 3 kids and groceries.
I am just like you. I hold the door open for people, help moms with small kids. Small acts of kindness really touch people's lives. The other thing I do is park further away from a store when I don't have my children - in hopes a mom with kids can park closer.