In your opinion, what is one of the most useful mechanical/electrical inventions of the last 150 years?
This one should get some interesting answers, given the many areas of human existence machines of all kinds have improved. I’m going to go with the ” in the home” category, and say that the most valuable invention is the automatic clothes washer.
Can you imagine the alternative? (And on the division-of-household-tasks list, doing laundry isn’t even my job.)