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