it's either one or the other, but when they do clash, i just end up dressing like this
if brit grandpa, it's loafers & socks, some pleated trousers, a knitted pullover with a basic white or black tee underneath. sometimes the pullover will be changed for an oversized blazer. if i'm feeling more sophisticated, the basic tee will get switched for a button up
if it's skater boy, you've seen enough of them to know the fits, but here's an example anyways: baggy pants (cuffed cause i am a hobbit and i refuse to swiffer the city streets with the hem of my pants), a band or graphic tee underneath an oversized hoodie or layered with flannel, converse/vans slip ons/adidas superstars, rings and a baseball cap