Why do you keep getting bad dreams?

The reason people have bad dreams is because of their thoughts just before sleep. Say, for example, James was thinking about his grandmother's death just a few moments before he went to sleep. Therefore he would be dreaming about death and would have a nightmare. The best way to prevent nightmares, or dreams of any kind is to go to sleep without any light, no music, and no television. Relaxation and beneficial thoughts work well in addition to the lack of sight and sound.