conversational landmines

Wow, seriously, that post from two years ago is heating up now! Anonymous vs. Anonymous... the battle of nameless, faceless posters!

I was thinking the other day about how there are certain things that I will just never ask someone. There are certain loaded questions that I think it's nobody's business to ask, due to the potential landmine the answer may be. The thing that surprises me is the nonchalance and flip manner that people ask each other these things.
Par example;

"Why haven't you guys had kids yet?"
This is a bombshell. I have, in the last three years, have had three friends miscarry (that I know about). It is an extremely difficult and emotionally wrenching experience to go through, and one that most people prefer to go through with only their closest family and friends. You can never know if a couple is unable to conceive, has discovered a health problem in their genetic line, or just had an unfortunate miscarriage. It is also none of anyone's business but theirs.

"When are you two going to finally get married?"
Same goes here. People these days may not be marriage people, or one person may be pushing the other person to pop the question... this is so potentially loaded, I can't believe how flip people are with asking it.

"Why don't you drink?"
Man, let me tell you. Of my friends who don't drink, here are the reasons.
- I lost a family member to alcoholism.
- I have a lot of alcoholics in my family, and I don't want to be like them.
- I am an alcoholic.
Do people think this is something someone they don't know well enough to know these things about wants to share with them?

Anyway, all this to say, think twice before asking people about these potential landmines... does anyone know any other bombshells people rattle off like it's conversation about the weather?