To play devil's advocate to your devil's advocate:

Of course, sometimes these are not choices that people make. SUVs get consistently vilified, but really, many of them aren't as inefficient as you might think. Certainly the tank-like SUVs are terrible on gas, but many of the smaller SUVs are indistinguishable on gas mileage from your average "family sedan" or minivan. As a comparison, the Ford Escape gets 22 city/28 highway, which isn't much worse than the Accord's 22/31. If you have kids to carry around (playing devil's advocate here -- you don't need a car that seats seven if you have a family of four!), having an SUV may just be more practical. And a lot of the price of gas has to do with the fact that people drive a lot, because mass transit in many parts of the U.S. is underdeveloped, inefficient, unreliable, or nonexistent, and many people have long commutes due to poor urban planning that's turned traffic in many cities into a hellish nightmare.

Likewise with fast food. You get an hour break for lunch. Maybe you can't bring a lunch from home, because your commute is so long that you barely have time to get in the shower before you leave for work. An hour probably isn't long enough to eat at a sitdown restaurant (where, by the way, the food is often not that healthy, either), or maybe it's too expensive. Oh, but you can eat McDonald's in less than an hour, and it's not that expensive. So it's unhealthy -- eating unhealthy is better than not eating at all.

Don't assume that all of these things are choices.