If you truly want to achieve harmony with a grumpy friend right now, you need to stop and get centered yourself. Stop doing what you think they want you to do and start just being real. When you strip away all the anxiety about what to say and how to act, you can see things much more clearly: and the answer will be clear. And get ready to do more than your fair share to make things right between the two of you. When it comes to things like this, you can't go tit for tat.