Now, the fun of this thread is to post idiotic idioms... it may be yours, but it can easily be "Uncle Bob's" or "Aunt Martha's", at any rate, you may not want to own it, but post it.
My Aunt (Bless her heart): Ya know a Tiger can't change its spots!
My nephew (Wasted is the excuse we will use): Man, ya know, its... um... its not like it's Rocket Surgery. Me (My reply): Or even brain science, for that matter.
I'd love to hear your idiotic idioms, you don't even have to own them, just blame some one else and share away.