Its about hindsight.
Hindsight is considered 20/20
Thats nice because with it we can make choices regarding the future in ways that we wouldn't have been otherwise without this rear view mirror 20/20
Believe me my body would be much much younger without having had any coffee.
I'm sure there are some people who lived through the 1960's that can look through their rear view mirror and say well I really could have done much better without such and such, even though I did enjoy it all at the time.