Do Old People Understand The Concept Of Time?

Why do old people have no concept of time? I mean come on... they have nothing better to do than to wait for death himself to come and relieve them from this world... They have nothing but time on their side. Old people think nothing of going to McDonald's and spending three hours sipping a cup of watered down 50 cent coffee while reading a four week old newspaper... But they somehow lack the capacity (or the common courtesy) to wait five minutes in line while you help the customer in front of them...