Whats UP down South

My kids call me often. Not for any specific reason most of the time, but just to see if I'm still there I suspect. When my son calls and I answer the phone, his first words are always, "What are you doing?" and my reply is always, "nothing much, what are you doing?" The other night, I thought I'd try a different tactic when he called to see what would happen so in reply to his "what are you doing", I replied, "What am I supposed to be doing?" That threw him for a loop and it took him a few minutes to remember what he had called about. Heh, that'll teach him!!