Why are missing values not ignored by default?

[adienes]

yes, we agree on that.

I think it got a little lost in the long thread, but I still currently stand by this one:

Why are missing values not ignored by default?

there has to be somewhere to draw the line ; not every function can propagate missing, but you raise good arguments as to why some of them should with that being said, I think my ideal world would be: binary operators propagate, statistical moments and quantiles (and cor and cov) skip, everything else MethodError, so mean(heights .> 5.5) would work just fine