Black Mold. It often lives undetected in houses. According to a 1999 study at the Mayo Clinc, Black MOld is the cause of nearly all chronic sinus infection. It can cause headaches, depression, hair loss, nosebleeds, and death. So faor the love of God, clean the damned house before you kill us all!
I'm not the tidiest person but that doesn't mean my friends shouldn't be. Sometimes I'll go over to a mate's place and think: how nice that you feel comfortable enough not to clean up before I arrive. So I tell them what Black Mold is. Ten minutes later they'll be disinfecting the linoleum under the fridge while I watch on, eating all the biscuits. You see, I have always liked biscuits.