I’m a pretty good judge of whether or not someone is happy. I know this because I’m very good at hiding what I really feel from people, so I recognize the tells. I think people do this because it’s in part, a defense mechanism. If you don’t let on how upset/sad/depressed/happy you are, people can’t hurt you or attack you or even make comment, because they can’t figure out the right angle. It keeps other people off-balance. I don’t ever use this superpower, if you’d even want to call it that, to hurt people, but rather to help them when they need it most but can’t admit it.
I find it depressing when people feel the need to hide their happiness from others, lest they think ill of them for something. Life is too short to placate people like that. If you’re happy, be happy. Smile. Laugh like a clown. Tell funny jokes.