My new car only averages around 17 miles per gallon. A few people I know have given me a hard time about that.  Here I am, polluting the environment. Making the US more reliant on foreign oil. Using up valuable resources. And so on.  What seems to get lost in those discussions is that it's not your mileage that should matter, it's how many gallons of gas you consume.

I put around 6,000 to 8,000 miles on my car each year.  I don't drive very much.  Longer trips involve the whole family which are in the mini-van.  So even though I only get 17 miles per gallon, I'm only using 400 or so gallons of gas each year.  Or put another way, a typical person with their 30 mile per gallon economy car driving 20,000 miles per year is using nearly 700 gallons of gas each year.

Personally, I don't care that much about how much energy other people use.  I try to conserve power when it's convenient (and sometimes when it's not so convenient).  But I also try to conserve energy in effective ways.  Not everyone can live close to where they work. I can. But it also means I use less energy to get to work. 

So next time someone gives me a hard time on my car's fuel economy, I'll have to remember to ask them how many miles they drive each year.