Comparing someone to Albert Einstein should be a huge compliment, right?
Saying something like "Way to go, Einstein!" sounds like a compliment but is actually meant to be an insult. One of my favorite comedians, Brian Regan, pointed this out and I thought it was hilarious.
"You don't know where you parked the car? Good job, Einstein!"
I don't know how using Einstein as an insult came to be, but someone started it and it just stuck. Sorry, Mr. Einstein.