Are there people you never come out to? Situations where it will do more harm than good? Or do you feel it's wrong to hide yourself no matter the cost?

I decided a while ago that I would never come out to my mother.  She's in her 70's and not in the best health. A few years ago my family and I thought she was going to die but she's recovered well since that time. I'm not sure how long she'll be around, another month or another 10 years. The last time I visited her she didn't recognize me for the first 10 minutes. My appearance has changed but not so much that she shouldn't recognize me. So it may be the beginnings of dementia. On top of all this she was the one who made sure I wasn't feminine in any way and she has a bad tendency to obsess over things. All of this together makes me feel like it will do her more harm than good. It's possible that I'll change my mind in the future but for now I'll pretend to be her son.

I'm never going to come out to one set of my grandparents (technically, they're my great-grandparents, since they're my maternal grandmother's parents). They're in their mid-eighties, and, even though they don't have any health problems (mental or physical), they are still very much a part of the culture they were raised in; basically, one should just politely ignore[deny] anything that seems unusual. The fact that they are very far-right leaning politically doesn't help, not to mention their extreme religioius conservatism, blatant homophobia, and disgust towards non-Christians.
I suppose it's somewhat ironic that I've turned out to be an atheistic gay transman who despises politics.
But because of this, I'm going to have to masquerade as a girl whenever I'm around them, but I was always considered a masculine girl, so that won't be too hard appearance wise. I'm just worried that since people will have to use female pronouns when I'm around them, that the people using said pronouns might fall back a few notches on the progress scale and begin to slip up more in other situation, if that makes sense. 

In any case, if they were told, they'd probably have a heart attack and die, so I'm not going to come out to them.

My grandma, she's in her 80's and she has Alzheimer's. It's really sad, but I guess if she was in her right mind then she'd probably disown me or something.

I rather not come out to my dad, i know he will "disown me" and i never really talk to him anyway. Me and him sorta hated each other at one point of time

Sorry to hear that there are family like you have said.
I really don't think they will have a heart attack though, just be really angry and dismissive.  If they are going to react the way suggested, you've lost them already, so they are not really family anyway.
Sad really.

Karen.

I'll probably never tell my uncle.  He's from a small, extremely conservative town and goes to a Harry-Potter-is-evil church.  Last time my parents saw him he was going on about how divorce shouldn't be legal because single mothers are more likely to raise gay children.  Yeah, that's not happening.  He'll probably find out eventually, but we don't really talk to him much anyways.