I do relax, my driving has become second nature. I don't think about it, I just do it. Plus I drive like 44k miles a year so my driving saves me like $1k in fuel.

As for hypermiling. I don't drive the speed limit, I drive the terrain, sometimes that's 75 in a 65, sometimes it's 45 in a 55. I pulse and glide, which means I get up to a target speed quickly then I glide, either in gear which is 0 fuel consumption in my car(tdi's don't use fuel in gear coasting) or in neutral on good long hills which doesn't have the drag of engine braking and only uses .2gph instead of 1-1.2gph+ to maintain constant speed. Occasionally I'll turn the engine off if I'm at a LOOONG stoplight because I've found they can suck 5-7mpg off your total. NEVER turn your engine off while driving/moving on a road, it's just unsafe and not worth the risk. I know my mpg numbers are actual because I fill to the lip of the neck EVERY fill, and have every fuel receipt from this vehicle. The best thing for fuel mileage is a Scan Gauge II, I paid $139.95 for mine and so far it's paid for itself.
I went from a pretty solid 43mpg average to 51mpg and rising, that's an 18% increase in fuel economy without anything but driving technique. I wouldn't say it takes me any longer to get anywhere, and I don't get frustrated on the highway anymore. Plus I get paid to drive to my stops, so why rush? Work doesn't pay for speeding tickets. Just coasting down the long hills in neutral would bring my average up to 48mpg with driving normal everywhere else. It's amazing what a lil high speed coasting can do for mpg.