There are two questions that always get me in interviews. The first one is the salary one. If I am evasive, or try to deflect, the interviewer will probe deeper. They just wont take no for an answer. In fact I've even been told straight up "Give us a figure, or we won't proceed".
Another one is about my children. They are five and seven and finish school in the afternoon, when they are collected by their after school service. Under EU law interviewers cannot ask about my family life, but they do. They ask what my children's ages are, they ask when the finish school, and crucially what happens if there is a problem that would require me to dash out to pick them up (illness etc). When I say my wife will take care of that they ask what she does for a living. If I say that I'd rather not discuss that then I can be certain no matter how skilled I am for the job, I wont be getting it.
In my experience most interviewers know all the tricks. If they want an answer to a question they will get it. If you don't play ball then you probably wont get the job.