The only item that seems to make sense it the normal Mushroom, but even that doesn't count because it makes Mario bigger on contact with anything on him, including clothing.
How Pac-Man able to eat ghosts after ingesting a Power Pellet, and why do they come back after a few seconds? Also, why do they stop granting this ability at a certain point in the game?
This item made more sense when it was called a "Soft." That version of the item was a potion you poured on a petrified party member to free them. How does the Golden Needle work? Is there a special slot for it? Even if it's enchanted, gold is a very soft metal, so it's unlikely it could pierce the stone if it was made into a needle.
How can pointing a fake gun at your head and pulling the trigger summon your Persona, and why did Yukari have such trouble doing it, despite knowing it wasn't a real gun?
How would the makers of artificial blood be able to account for the different blood types, and how would they make sure it wasn't treated as an infection by the patient's immune system?