Back when I was an entitled, and all knowing, teenager -- rather the parent of three -- when my father had had enough of my demands (of my family and the world) and my dismissals (of anyone else's advice or logic) he would say "you haven't washed your hair in while, don't you need to do that?" At the time, I was as likely to get up and wash my hair, as I was to be insulted. Now, I realize that he was showing me, rather than telling me how small my world was and how little I truly 'knew.'
Many years later, when my daughter was at overnight camp (and then boarding school and now college) and would call me and go on about various injustices wreaked upon her by her peers, her counselors/teachers (aka her elders) and most of all the world as we know it (...it's not fair..) I would eventually say her, "why don't you take a shower? That always makes you feel better."
It took me years to see that I was (once again) emulating my father, and passing on some of his best advice.