Hi how are you?

Doesn't it bug you when you get to a checkout line and the clerk says "hi, how are you?" when they really don't want to know? Why not just say a simple "hello". I tried saying "I'm fine, how are you?" and nearly all of them completely ignore me as if they don't hear. Suppose we were to go into a long tirade of our daily trials and tribulations or telling them how great everything is and start showing them photos of our grandchildren or favorite pets? They would think we were nuts, but they asked!