The only thing I've ever made that was a total failure was a recipe that was my grandmother's. A few months before she passed, I was visiting with her. I asked her to make her famous (okay, probably only in the family) maple raisin cake. I sat there and helped her, but I was also writing down all of the measurements of everything. I also wrote the timings and all of the steps.
I then lost the notebook, after only making the cake on my own twice. (More than likely it's somewhere in my house, but there are so many hiding places...and who knows, one of my kids might have needed a notebook for school and I accidentally gave it to one of them!)
I tried making it from memory. That was a disaster. I then called two of my dad's sisters, thinking they'd have grandma's recipe...to no avail. Apparently I was the only person in the entire family that my grandma trusted the recipe to...and I have lost it.

If I ever find that notebook I, not to mention my dad, will be ecstatic!