While it is desirable and admirable to generally have a cheefull, friendly demeanor, I think this article errs in trying to make a grey issue into one which is black and white. Most people have a mixture of thoughts. There is a huge debate about how you would define 'good' thoughts and ' bad' thoughts. I think it is obvious from the news that sometimes people have been abused by people who looked friendly. The conman has to be skilled in appearing friendly and honest otherwise no one would be taken in. I think it is actually a form of bullying and insult to equate appearance with thoughts. Some of the most carefree people are capable of making the cruelest, most exaggerated statements. i would agree that it is preferable to be self-controlled and not become overly angry, to try to put the ideas in a polite and friendly manner but we all get angry at times, it is just part of life. There is a place for all our expressions, happy, sad , nervous, confident, angry , pleased.