Never rain on someone’s happiness and never deprive another person from being happy or becoming happy. People are fragile and for a lot them happiness is all they have to look forward to or enjoy in this life. So be nice.
Try not to give up on people to easily or too quickly. Things change and people change. And related to that, always give everyone a second chance, if they do it a third time, run away from them and never go near them again.
If you are going to lend out a book, just assume you’ll never get it back.
Avoid sarcasm because people are much, much, much more touchy and insecure than you will ever truly know and sarcasm scares them.
It isn’t true you should not burn bridges. Sometimes you have to burn bridges for your own good. Just be selective in the bridges that you burn.
If you should ever come across a person who has nothing to lose, run like hell away from that person and never, ever go near them or anyone else who has nothing to lose.