An ass out of me and me?

Assumptions and stereotypes are a mental sucker punch. Boy do I feel like an ass...

Yesterday, while standing in line for my prescription at Target, I observe a small family dynamic. Both children, boys, are dress in monochromatic blue. Jeans and serviceable shirts, nothing fancy. No logos or "bad attitude" sayings on their clothes, just two plain but clean boys. With them is their mother. She is wearing very simple black flats with nylons, an ankle lengths moss green skirt, a white button-down collared shirt and matching moss green hip length vest. Her obviously very long hair is pulled back into a severe bun at the nape of her neck. She and her children spoke with an accent, that I could only describe as Eastern European. To my eye, they appeared to be a very strict and simple family. I assumed they were something like Mennonites or Amish. So imagine my surprise when out of her small and plain black purse, Mama pulls out a Blackberry and starts to talk to someone.
Honestly my brain was stuck on stupid for a second- I just couldn't reconcile what I was seeing. But fortunately my brain finally became unstuck and kicked my own ass for being dumb. Just because someone is dressed a certain way does NOT dictate who they are. I should know this very well, considering my profession. I just found my own stereotypes and assumptions to be funny. Makes me wonder what people assume about me? Maybe I shouldn't ask...