When I have a bad dream, wake up, and go back to sleep, my mind loves to replay the original dream. So I try to adjust it. It isn't that it will fix the past, but it allows me to get some peaceful sleep instead of reliving the trauma over and over again in my dreams. Sometimes it works and sometimes my mind is just set on torturing me. But I am grateful for the times it does work. Sleep is cery important to mental and physical health. If dreaming about a better ending will allow you to get restful sleep, don't you think that alone is worth it?