The phrase of choice of a very loud Armenian male population, especially from Glendale, CA when they disapprove of anything not to thier satisfaction. Normally said in a very loud, booming voice with a rolling 'rrr'. This phrase is used mostly in driving situations where the all too perfect Armenian driving style has been disrupted in some way.
Shouting from his driver' side window - "Hey BRO! Not Cool Bro! Why you make lane change my lane when you KNOW I coming BRO!?? NOT COOL BRO!!".