While Gosling often looks great on the red carpet, he's not always quite as fashion conscious when he's out on the town. In April 2011, he was in Toronto shopping for vintage clothes and wore a thin white undershirt with a heavy overcoat. This is a classic example of impractical dress. Is it cold enough for that coat, Ryan? You've only got a T-shirt on underneath it, and you haven't buttoned it up to keep you warm.
The lesson here is to dress practicality. Sure, you should try to look good, but dress seasonally and avoid wearing clothes that would make you obviously uncomfortable. Gosling was either stifling under the heavy coat or freezing in the tee. The clothing you wear should always make sense.