I rode a decade every day work/home/shop/leisure with a 2 x 7 gear. After a drivetrain replacement on the biggest front and smallest rear until it started to skip then I rode the second smallest rear until it skipped then again drivetrain replacement.
At some point, with one bike in the lbs awaiting repair since 6 months, and the other bike skipping the second smallest, I decided enough and went singlespeed>fixed.
So in fact, I never used gears. I pushed harder instead. I remember at a time I decided to buy a new bike, that the new bike had a smaller chainring mounted without dealer asked me or me asked him. After a month I still couldn't get used to that having to spin around alot, and I asked another dealer to mount the size I had before.
Sometimes, with strong headwind all the way and/or bridge up, I nearly stall and it sucks. But ohwell, seen over the year, it's just a very minor distance that way.
Ofcourse, that's just my case. I don't care much about average speed / efficiency, if I get the work done and I've trained my bio stuff rest of life gets easier.