On the other hand "smile by default" doesn't tell you if the person is really happy or just wearing the default smile. As the article says "Indeed, when the Russians smile, they show a sincere and an open smile. The American smile does not mean anything really." If you see a russian smiling, you can know for almost sure that there is something either great or funny happend to him. When you see a smiling american, you just see an american that is not too upset.