Maintaining Cleanliness

The Gemara in Masechet Hagiga (5a) teaches that it is forbidden to do something that revolts one's fellow. The examples given include expectorating or killing a bug in somebody's presence. A modern-day example would be leaving one's used tissues on the table. The Gemara warns that one is liable to punishment for such behavior, for doing things that cause others to feel revolted. By the same token,…