I am evasive when they sound derisive. Truthfull answer is fitness, gas prices, stress relief, and weight control. Did I mention fitness? I tell serious people the long answer. Others I just tell to make the gas people go broke. I'm afraid I'm a most abrasive person. As I think of it, I bought a full tank of petrol last January and the fuel gauge is still on the full mark. Anyway, good luck and God bless. Blues Frog