I agree about not thinking about people being "smart" or not. I think everyone's interest just varies and sometimes their interests intersect with what people think of as "smart things".

One of my friends called me a genius the other day, but I'm just really nerdy about something that makes money. He's really into comics and is a walking encyclopedia of characters, timelines, stories and arcs, but wouldn't consider that "smart stuff", even though it is to me.