I know my gas mileage is dominated by flooring it down on ramps, but my mileage is still affected by a lot of other factors. I track basically everything I do with my car, along with mileage, and small things make a surprising difference. I can detect a change in my fuel consumption based on what tires I have on my car, how old my oil is, whether my roof rack is on my car, and whether I have my bike mount on my rack.

Those effects are noticeable on my normal commute, where I travel 8 miles and spend most of the time going less than 30 mph, where aerodynamics doesn't matter that much. When I take a road trip (and thus don't have to perform any suicide merges), the difference any of these things makes is quite substantial. My summer tires are each about an inch wider than the tires I have mounted on my old rims, and switching to the narrower tires makes more of a difference in mileage than taking off the roof rack. With the narrow tires and no roof rack, I can get about 36 miles per gallon at 55 mph, and with my winter tires and my roof rack on my car I can't even approach 30 MPG.

For a tech-related example: I prefer to use my phone with the backlight turned all the way up, even though it uses an additional 15% of every full charge, but I uninstalled the Facebook app because it used 3% of every battery just running in the background.

I'm just trying to be efficient in my own way, I'm not competing on efficiency.