Here is the full list of all 12 Karen: An Outrage Simulator achievements.
Lose your cool at the Con-Mart
You have reached the ultimate form
Nobody's having a good time if you aren't
Nobody tells you what to do
Rage at the restaurant
Erupt at the grocery store
Go ballistic at the spa
True serenity, through the misery of others
Spoke with the manager, and destroyed him
Throw a tantrum at the Starcups
Expiry dates are just suggestions
You are now Karen