My first MIL was an amazing cook, and her cheesy potatoes were the best I'd ever had. I spent 3 years trying to replicate hers, hundreds of hours, trying everything I could think of, and I finally got mine pretty close to hers!
So one day, I brought mine to her, all proud, and said "Taste these, and let me know what you think!"
She did, and she liked them. And then she told me hers were the Betty Crocker Au Gratin potatoes from the box.
Ouch.