It's changed my perspective on efficiency. There are some forms of inefficiency that can provide a buffer if something goes wrong.
Though Americans were probably least affected by WW1 and WW2 of most war participants. Go ask some people in Russia for a better example.
Eg flush toilets are a great time saver. But they use a lot of water.
If we had a drought tomorrow, we could switch to compost toilets. They are more hassle to use and maintain, but use basically no water.
Which one is more 'efficient' depends on the relative scarcity of water vs time.
It's changed my perspective on efficiency. There are some forms of inefficiency that can provide a buffer if something goes wrong.