Might I suggest that your question is rather vague. It also requires anyone attempting an answer to speculate on how societies/environments will be in future times. Something I think you might agree would be hard to predict given how much humanity has progressed and altered environments in say the last 250 years. Change that is advocated and appears to be progression in our time frame may result in catastrophe if applied to future circumstances. It may be the case that an action we view as abhorrent now will be necessary due to events we have no control over and are unable to predict. One must also take subjectivity into consideration. The vision of how we progress will differ greatly across cultures and societies as well as on an individual level. Having said all that I will still attempt to give your question a positive although very general answer. The ignorance, be it willful or not, that humanity as a whole seems to exhibit and in some cases embrace at present will be regarded as a shackle that once we are free of should never be allowed to return.

Misogyny.

There was a time when most so-called educated people thought slavery and child labor were part of the natural order of things. How will future generations judge the prevailing attitudes and behaviors today? How might our normal be deemed repugnant in the future?
(I am conscious that slavery and child laboir sadly still exist.)