"That's Stupid"

I told a friend of mine about my plan to start picking up trash. Not a lot of trash, but I mentioned that I had bought an upright dustpan and a broom, and was planning to spend a few hours a month picking up plastic cups and fast food wrappers.

"Why?" he asked me. "That sounds like a stupid waste of time."

I shrugged. "It's pretty good exercise. It's hard not to want to find an excuse to be outdoors when you're living in this town."

He smirked, clearly not satisfied with that explanation, and still unsure of what to think of a person who would go around picking up garbage on the sidewalks with no direct benefit to himself.

A moment later, he added, "Well, come over to the neighborhood where I live. We need you over there."

I don't think you get to criticize someone about the validity of what they're doing, then in the next breath ask them to do it for you. But people will criticize this kind of behavior, purely because they don't understand it.