I notice sometimes a forbidden topic can be like a superstition. For example I used to work at this big place where people could come and go. This one woman was just pure evil and was hated. About 4 times I heard someone mention her and begin to talk about her and another person (a different person each time) would say something like, “Hush! Don't mention her. Don't conjure her up! Don't talk her up!” Meaning sheer talking about her may uncannily bring her around.
Also I have seen this with employment anxiety and I must say I take it seriously myself. At work or away from work it can be very uncomfortable for people if you say that you have a secure job and will be there forever or your company is rock solid. That is like asking for trouble. I am superstitious enough that I'd never say that.
Another difficult subject can be health and I learned this as a tot from my older relatives and fast-forward because I practice it now, too. That is if you've been ailing or have something wrong and somebody asks how you are doing it is almost like if you say, “Oh, I'm all better. I'm much better. It doesn't hurt anymore. etc., etc.” - your problem will come back within hours!
I don't know what to say about these ideas. I've experienced them so I know people, at least some people, heed them. It is almost like words have power.
I remember seeing a sign somewhere that said “CAUTION: Be sure brain is engaged before putting mouth in gear.” LOL!
I know what you mean about “tempting fate”. My whole family is like this. We’re almost afraid to say that we’re feeling good or that things are going well. It seems like every time I get my hopes up about something...and say it out loud...something bad happens. People are always saying how you should think positive and walk on the sunny side of the street. I’ve never had that kind of cock-eyed optimism. I tend to think in terms of what can go wrong and how am I going to deal with it. Plans go awry. It helps to have a backup.
I guess there aren't that many things that I won't talk about for fear of making them happen. I'd love it if we could just make Hillary go away by not talking about her, but I don't have much faith in that technique.