A word that describes feeling grouchy, grumpy, you're having a bad day and raging at anyone that approaches you even if just to ask you if you'd like a cup of coffee. Typical Oscar the Grouch behaviour.
Guy: "Hey Sarah, would you..." (interrupted)
Sarah: "GO AWAY AND LEAVE ME ALONE"
(Guy hurriedly walks away)
Guy: "Man she was rather oscarish today"