Peter D: In other words, you might have taken a lesson from former SecDef Donald Rumsfeld, who famously said, back in 2002: "As we know, t
here are known knowns. There are things we know we know. We also know there are known unknowns. That is to say we know there are some things we do not know. But there are also unknown unknowns, the ones we don't know We don't know".
It's those doggoned "unknown unknowns" that spoil our plans.
Or, as Robert Burns put it, "The best laid schemes o' mice an' men Gang aft agley."