#9 Grapes
Similar to eggs, grapes are also an explosion hazard. But unlike eggs, grapes are made of just the right material that when they interact with the radiation from the microwave, they will turn into a plasma like substance. It may look cool at first, but you won’t be saying that when the grapes explode and your appliance is ruined.
But not being able to heat up grapes in the microwave shouldn’t come as much of a sacrifice. Because really, who needs to heat up grapes anyway?