2. Taking the Ex's Side
Speaking of exes, don't ever take the exes side in an argument or break-up. Your job as a friend is to make sure that your girls look as innocent as possible. We don't care what they did, you stick up for your friend and then talk crazy to her afterwards in private. Never bad mouth your friend in front of her to the ex, never agree with the ex and never go behind her back and badmouth her to the ex. It makes you look shady and disloyal and no one wants a friend that doesn't have her back.