It matters for the big things, but not for "stupid bullshit" as my dear wife calls it. Obviously there are things where principles and correctness are important

It matters for the big things, but not for "stupid bullshit" as my dear wife calls it. Obviously there are things where principles and correctness are important; but what are they? It seems that we should prune the set of important things down to the minimum needed, so that we are not paralyzed by unimportance.