Mushroom dissenters are scum and should be forced to eat nothing but Spam. In all seriousness though mushrooms are fucking great and always makes a dish 10x better whenever I add them in. Not to mention mushrooms, pepperoni, and jalapenos are the holy trinity of pizza toppings.
As for the whole fungus thing, potatoes n shit literally grow in dirt and absorb the yummy nutrients in the soil, poop and all. Bon appetit!