My normal expression tends to come across as angry-looking to people. :x
It gets annoying, then, when my parents call me out on it and accuse me of always being angry or in a bad mood, and then tell me I should "change my face" whenever I tell them that it's just neutral.
Lol, I'm the same way with some of my emotions. I have a hard time emoting, so my angry face is just dead placid, and my friends have learned to pick up on it right away.
Happiness is just one big grin though.
You should make a joke out of it with your parents. whenever they pass by, scribble your current state on a piece of paper and hold it up for them to see.
If you take the piss out of them, then they'll stop bothering you.