What?

Two elderly gentlemen in the bus, catching up. In the middle of the conversation, one said, "when I was younger I used to walk down there." The other replied, "you used to work down there?" From across the aisle the other shouted back, "walk, walk, I didn't say anything about work!" Then referring to the backpack the other held in his hand, he asked with a grin, " are you going to work or to school?" To this query came the response, "yes."