Visit a recipe site and find a dish for which you have the ingredients. Sort the different versions of the recipe by rating.
Invariably, some users will rate a recipe five stars. Then, in the comments, they'll explain that they made substitutions.
"This recipe is so simple and delish! I didn't have eggs, pepper or salt, so I used macaroni. I replaced the beans with gummy bears. I also doubled the worcestershire sauce. DH came back for thirds!"
You made an entirely different dish, but promoted this one to the top. WTF? Have you no principles? Why do I know what 'DH' stands for?