This is interesting and the point that objectives matter is a very good one. I own a lot of nerdy tshirts. A few years ago I went to an event that was a geek singles event. I deliberately didn't wear a generic nerdy tshirt but rather wore a math tshirt because it efficiently singled what sort of nerd I was. In that context that was likely a better approach than dressing in a way that is generally considered to be fashionable. Goals matter.