Experience is a great teacher, especially when it’s someone else’s. These examples were submitted to learnfrommyfail.com:
"When trying to compliment your girlfriend, tell her that she is prettier than her sister, not that her sister is uglier than she is."
"Never name a goldfish after your child, or his younger brother might go to school and tell his teacher that Eric died."
"When a coworker calls to say she’s going to be late because she ‘has to wait for the paramedics,’ don’t respond, ‘Okay. Have fun!’"
"When your boyfriend is rehearsing for a play, don’t tell your roommate that he is ‘upstairs doing lines.’"