Absurd phrase used to distract, deflect or add irrational levity to a conversation. Typically used by ignorant people who have no useful knowledge or relevant input to a discussion.
"I believe the Schrodinger equation fails to calculate the probabilities of certain outcomes in any state of the quantum system, what do you think?" "Have a cookie!"
Sarcastic phrase ever. Most likely used as a response to someone who points out the obvious.
Person 1: Hey, Earth was created by God.
Person 2: Have a cookie.
"Go Fuck Yourself"
When engaging in a debate and the opposition is too dim witted to grasp the concept so you politely suggest they, "Have a cookie."
Most effective in public places or in mixed polite company.