I totally agree. I know it sounds strange, but sometimes I'm just too tired to pretend I'm happy, which if I'm ever happy that's usually what I'm doing is pretending I'm happy for the benefit of other people and not because I really am. But sometimes I just want to be in a bad mood and I want to be left alone. You always have people coming around telling you to "Cheer up" & "Turn that frown upside"
And it's particularly annoying in the morning because I am not a morning person.
Before I've had my coffee I don't want anyone saying a word to me. I hate people who are cheerful in the morning.