Seen on the (data visualisation) Edward Tufte site:
You have already quoted a short version of John Tukey’s aphorism, but I prefer a slightly longer expression of the same idea that he wrote in 1962:
Far better an approximate answer to the right question, which is often vague, than an exact answer to the wrong question, which can always be made precise.
Somewhere he also wrote (but I’ve been unsuccessful in tracking down where or when I read it),
If a thing is not worth doing at all, it is not worth doing well!