I couldn't decide which of the first 2 options in the poll to select.
I am not ashamed of it and will tell anyone, but really do only tell friends because it doesn't often come up in conversation with say co-workers or other randomers.
Other than at forced ice breakers where you have to stand up and say something about yourself, I do feel I shoot myself in the foot and look a social outcast when I say my hobby is studying Japanese, and I listen to Japanese music and watch Japanese TV shows for fun as well as study aids.
I used to hide this, but these days I am more of a take-me-as-I-am kind of person and don't go to lengths to disguise it anymore.
Then again I also see it as a way to test if there are any other people with similar interests in the room, or at the very least the people around aren't the sort to judge and make-fun. If they are I find out straight away that there would be little to no point trying to make friends with them as they would not be the sort of people I want to talk to anyway
On the flip side of that, if anyone in an ice breaker ever says anything vaguely interesting or unusual I will use it to go talk to them and try be friends. Even if it is something I am not into myself I appreciate the fact they are not afraid to admit it and like something other than "football, shopping and going to the cinema/gym" and all the other corporate standard answers.