This is really awesome of you to try and do because we're not supposed to burden everyone with our problems. But people do assume stuff (and make themselves look stupid) and maybe think "hey this girl would never understand me, she's so happy" which is a dumb assumption but it happens.
I think I have the opposite happen with me..kinda. I'm kind of more reserved and quiet especially around people I'm not super-close to which ends up being most of my congregation. Even people I've known forever, like those in my bookstudy, make jokes about me being the dark queen and always being gloomy. I'm not being gloomy I just don't feel the need to be bursting with smiles and sunshine especially at 9:30 in the morning!
I think a lot of us have trouble finding the middle ground.