1. Personal Grooming. Anything involving tweezing, clipping, buffing, or polishing of anything on your body should be confined to the privacy of your own bathroom. Notice, I said your own bathroom. It is not okay for me to step on your nail clippings when I get out of the shower.
2. Sex. It seems like this should go without saying, but just for the record, full copulation in a public place should be avoided. This goes double for a confined public place like, say, a bus.
3. Unloading of Family Secrets. A crowded train car is not the proper location to tell your brother he’s adopted. No matter how much you hate him.
4. Angry Breakups. Take a cue from the now infamous Burger King couple. Sure, the public might be entertained by the drama , but do you really want Twitter littered with your problems?
5. Private Cell Phone Conversations. You might not have an issue with talking to your cousin about her STD while you wait in line at Starbucks, but chances are she assumed the talk wouldn’t go any farther than your living room walls.