Ravioli... when making ravioli from scratch, with a stamp, I started adding flours to the wax paper later... and the first ones got stuck to the wax paper. The first raviolis began tearing when trying to get them off. I was not pleased... and my dad wanted me to calm down and I tried to explain that making raviolis from scratch is labor intensive and losing 1/5 of them was very legitimately worth cursing over.
Yeah... anything you bake, put pasta sauce on the surface!
I otherwise rarely make mistakes in the kitchen, as I rarely go by memory (either it is to taste or in the recipe and my written mods). I once forgot flour in a coffee cake. Yeah... flour. And baking soda in a banana bread (turn banana cake). The later was fine, the flourless coffee cake... I'm still not certain how I messed that up. Added only one stick of butter to a cookie recipe (needed 2), however, that was when I learned that subbing an egg for a stick of butter makes the cookies more cakey, so umm... yeah, I meant to do that.
Oh, I repeat mistakes frequently, which is why I wanted to start this thread.
For example, I love putting unsweetened chocolate in chili. It adds a vaguely mole-ish kick to it.
But the moment you add that chocolate, you need to stir the pot more frequently, or else you get a burned crust on the bottom of the pot that ruins the flavor. I always forget to stir more frequently, so I really should stop putting unsweetened chocolate in my chili, but unfortunately I have a memory like a sieve.
