I used to have a friend who said, "You can get cheerful or obedient, but not both at the same time."

I do think there is something to the saying "fake it until you make it"...I am not saying to deny your true feelings, but there are studies that have proven that your body chemistry changes when you smile, take yourself out of your sadness with a kind word or helping someone, etc.

I think sustained cheerfulness all the time is a bit annoying and unrealistic..interesting article

No shit you cannot mandate cheerfulness

I don't think the great philosophers were known for their sense of humour.

I noticed this while volunteering at two nursing homes:

Cheerful people make more friends. Everyone wants to be their roommate.

Positive people heal faster, and have fewer post-surgery complications than negative people. It's well-documented.

Oliver Cromwell would have pleased the ancient Greeks with his banning of any activity that encouraged cheerfulness!