I think the "You idiot!" headdesks are more about hearing someone contradict themselves or ignore the evidence about the consequences of the choices they are making. Or instances where the person really has no way to know why they are suffering a consequence but won't listen to reason when offered an explanation. Like, if I complained about being tired or hungover after those martinis and that dancing, "WHY is this happening to poor little ME?"
You wanna eat cheesecake on your birthday? Enjoy it. Living your life always doing the "right/healthy" thing would bored me to tears.