In his self-portraits Vincent van Gogh varied endlessly with his look: man with hat, man with pipe, or with hat and pipe. He always looked serious. This had nothing to do with his mood, but was common in the 19th century. Many people had bad teeth, so portraying himself laughing was not an option.
Vincent used a lot of orange and blue for this portrait. What colours would you pick? Blue and orange just like Vincent van Gogh? It's up to you!