It's spring, warm and humid and the place is crawling with huge brown cockroaches. They are disgusting looking things but they don't make a lot of noise, unlike crickets. I have noticed they can go anywhere, including up walls and across the ceiling. I try to keep my place spotless but it does not deter the creatures. They come in through vents and under doors and are really bugging me (sorry!). How harmful are they? I don't like the idea of them crawling across anything I might eat but is their awfulness most aesthetic?