The average famous sayings are generally and logically stupid:
"You can't have ya cake and eat it too..."
People misuse "let them eat cake" often too.
Or even just "piece of cake!" What if I am diabetic? Then a piece of cake is not a piece of cake, it could be a medical emergency.
"Easy as pie!" Depends on the pie, some types of pie are difficult and time consuming to bake. Especially if you don't do the crust right, then you just have a mess.
"Whats good for the goose is good for the gander." I have no idea what a gander is, this phrase is not helpful in my everyday life.