What happens when birthday paper is thrown out?

Not so good. Don't throw it back to your loved ones. This will hurt your luck. If you think littering is harmful, you will get what you deserve. As long as you are willing to hurt others, your happiness, your life, or your descendants will be deprived. In the long run, a person who harms people everywhere will come to no good end. Please go and see more bad people at all times and in all countries.