It was metaphorical ass kicking. You start to reevaluate how difficult your challenges are when you start talking to someone who invented the first internally programmable computer.
Actually, the common slang you wanted was "a kick in the ass" or less vulgarly "a kick in the seat of the pants", as in this book's title, http://www.amazon.com/dp/0060155280 . An "ass kicking" is slang for a beating.
