Cliche Scrutiny

I always look at cliches and exam them for flaws in logic or question its intent. One such cliche is the idea of the unintelligent being "mouth breathers". Now, I consider myself a somewhat intelligent person, yet I am definitely physically, a mouth breather. I note that about myself because of a science lesson from third grade in how breathing through my nose is healthier than the mouth and I had a hard time converting to a natural nose breather. Now, in recent weeks I have been a babbling mess of a man whose brain is a swirling Sargasso of stupidity retracing the same steps of my failed relationship over and over again, and I note in my stupidest of thoughts I am breathing hard through my nose, like a mad bull, which indeed is how I feel sometimes. So, I guess I dispute the idea of mouth breathers being stupid, Duh!