Mine is the computer. I continue to be amazed at what we can do with them.
Plumbing. I could live without almost every modern comfort but a flushable toilet
I was going to say HVAC. It’s cold as all fuck here in the winter, and hotter than donkey balls baking in the sun during summer.
To expand a hair on this, modern waste disposal. So with plumbing comes sewage. Then the close child is refuse removal. We literally cannot live (healthily) without these things.
Side-bar, the folks that power waste removal are VASTLY under-paid.
Waste removal is usually a premo paid job, yeah they could be paid more, but still pretty cushy pay for most of them. It’s not some minimum wage job and the entry barrier is usually high school education.
Depends on where you draw the line. Janitors for instance are usually paid a pittance. As are cleaning crews that vacuum the vast offices spaces around the country.
If you are talking about CDL drivers that collect trash cans then yeah, they tend to be paid well. Without all the pieces of the puzzle though the system breaks down.
Plumbers, as it turns out, are paid quite well since nobody wants to go into the trades currently.
I would rank plumbing pretty high to be sure, but without the steam engine to drive the water pumps, plumbing is limited to aqueducts, gravity sewers, and intermittent, low-volume supply from animal or wind-driven pumps.
Even today, the overwhelming majority of our energy passes through a steam phase at some point. Steam power is by far the most important discovery/invention of the modern world.