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