Mine occasionaly pulls something similar to this. My revenge is a little more stealthy, sometimes he doesn't know he has been 'got' till it is over and done with.
I had bought some fat free creamer for the coffee (cheap and generic). He said it tasted funny and refused to use it. Of course, I had purchased 2-3 containers as it was such a good deal. So I bought him his coffeemate creamer and started mixing it. Took a few weeks to use up the "CoffeeMate/generic mix" but he had NO IDEA. NEVER noticed a taste difference or anything. He ALWAYS makes comments on the taste of EVERYTHING.
Fast forward to a few weeks ago when he decided to go on a diet and use the fat free stuff. He went to looking for it, asked what I did with it. I told him that stuff was used up LONG ago. He didn't believe me and knew I didn't use that flavor. I admitted to what I had done and then he says.....wait for it......
I KNEW IT TASTED FUNNY! I said yea RIGHT!!!
Revenge was Sweet....fat free but sweet!