At my Bar Mitzvoh ‘party’, I took several styrofoam cups and poked a tiny hole in the bottom of each one and put them back in the stack of new cups.
Someone took the first one and of course it leaked, so they took the 2nd one placed it under the first one to catch the leak, and it too leaked, same for cups #3, #4, and #5…All stacked, one inside the other and all still leaking.
Finally they gave up, saying “These cups must all be defective”.
If they had taken just one more cup it would have worked because I only did it to a few cups.
Hasghacha Protis applies to practical jokes too 🙂