also i tend to think teenage!dean was harder-looking than teenage!jensen

Oh, I imagine he did everything possible to look tough and manly but like you said he just can`t help the pouty lips and the long lashes and the perfect facial features. *g*
In the hunting world where the average citizen tends to go more towards Pa Bender in appearance he would have stuck out. And if he did start hustling as a teenager, he`d probably have attracted some unwanted company/propositions.

I just see the majority of his attitude coming from that then any feelings of true superiority and general asshatness like people might think when they first meet him.