What are we wrong about today?

In the mid-1900s, you didn't pump your own gas. All service stations were "full service," so they would pump the gas, check your engine, tires, etc., and clean your windshield. Looking back, that seems insane; who would want another person all over their car at the gas pump?

The argument was that it wasn't safe for a person to pump their own gas. Training was involved to ensure there were no fires or malfunctions. Of course, today, looking back, that argument seems absurd. Of course, pumping your gas is safe! But that was the thinking at the time, and everyone accepted it.

This has me wondering, what do we all accept today that will seem ridiculous 70 years from now? We have to assume there will be many things unless we choose to believe we have everything figured out, which is never true. So, what habits, rules, laws, or ideas are we wrong about? What conventional wisdom from today won't be wise tomorrow?

I don't have an answer, but I love to ask the question. What do you think?