There’s a big different between knowing what to do, and actually doing it.
Whether it be in our relationships, our diet or fitness, our finances, or any other area of life, there are plenty of things that we all know to do—things that are “common sense”—that end up being not that common in practice.
The issue is not more information—we already have more than we need—but the will to act on what we know. Without action, all those common sense things we know do us no good. Because they only have impact when we actually put them into practice.