In a word, it's subjective.
As we move through life we humans enjoy extracting pithy and broad nuggets of wisdom from our experience as we introspect. Occasionally they are even generally true! But as I've grown a little less naive I've come to appreciate that most broad observations, as convincing as they may appear, are usually incredibly subjective - to the originator (among which I include myself) they make 100% sense, but devoid of the context from which they derived (as they are often presented) they are usually little more than noise.
It's the horrible gnarly truth of the world that we must become comfortable with to stop making these oversimplifications. </ armchair philosopher>