Controlling your state when YOUR having a bad day

I've started realizing that truly charasmatic people do not lash out on other people when they are having a bad day. Treating people like shit because your not in the best mood is actually a very weak thing to do. I understand you can't always be sunshine and rainbows, as MW talks about in his "Black Nimbus" lay report, but being nasty for no reason is something a chick would do! haha

Does anybody have any advice regarding staying composed on a bad day? I personally turn into an asshole when things don't go well, It's defintely something I learned from my dad gorwing up.