"Any idiot can smile. Idiots tend to"

An extreme generalisation which I find very offensive.

While it's inappropriate to smile in many situations and there are times when it is necessary to adopt a serious disposition, there is is no need to be a "soor puss" either.

Many people have a natural "sunny" disposition but that doesn't make them idiots. Of course, I don't agree with those who "force smiles" or pretend either. Why be something you are not?