So Much Anger

The boss strikes again. It started at 7am this morning. As soon as I walked through the door his negative attitude covered me like a dark rain cloud. He was upset because three employees were not going to be in today, and he had plans to leave early.
He said his usual "I can't ever leave. I can plan something six months in advance and some one will call in sick and ruin it". There is a grain of truth to this statement. In the past people have called in sick on days he had planned to leave early, but it happens less than 5% of the time. However, it's that 5% that sticks out in his mind and sends him spiraling into pissy rage.
I really need to give him the number of a therapist. He's making me lose my mind.