6. Lending other people money, or cosigning on a loan
First of all, co-signing on someone else’s loan puts you in a uniquely vulnerable position, you may think that you are helping a friend by lending your good credit reputation but if something goes wrong, YOU are responsible for the entire loan amount! Not only that any missed payment by the borrower will negatively affect your credit score.
As for lending money to a friend, the simple truth is that not only should you not put yourself in a position where money can come between your relationship, if the friend decides to delay paying you back or just not paying you at all, you will be the one losing out, not them.