When I find myself getting really grouchy I usually warn my son. Kind of give him a heads up so to speak. I try really really hard not to take it out on him no matter what I am upset about because I have been on the recieving end way too many times. I also know that if I am angry and start screaming at him he is gonna get angry and start screaming back at me and then it just keeps going. When it gets to where he is the one I am angry at I will usually step away to collect my thoughts. I will take a bath or something to relax and I usually calm down alot and I am able to "discuss" it instead of yelling. Or there is always the thing my mother used to do, lol. Count backwards from 20.