I usually fly economy because I can't justify the price difference. An extra $1000 on a 4 hour flight works out to $250/hour and I've done worse jobs than sitting in a crowded plane, for a lot less money. Plus it helps pay for the 5-star hotel at my destination. Of course, waiting at the Centurion lounge before the flight and having priority boarding help ease the pain.

When I do fly business class (usually on points), I'll admit that I do enjoy the look of envy as the economy passengers walk by, but only because I know that feeling myself.