Lack of sleep is one of the causes. Another is hunger. I know it's simple but if we pay attention to these two things, it is surprising how different a human can be. Try to have meals on the table an hour earlier i.e. 11am lunch 5pm tea. Because I realized that my hubby gets angry just before lunch and just before tea. And snack at 10am and fruit breaks at 3pm helps a ton. Just pay attention to the times he gets angry -- usually before meals. My husband also had a snoring issue. He had chronic sleep apnea but improved so much when he's on the cpap. He can last without the CPAP if I turn him to face down on the pillow until he can breathe normally while he sleeps.