When someone starts asking questions that seem to be too personal (salary, living, etc.) - could you say something like "could we please change the topic?" Or think of a vague non-answer to have it ready (like "they never pay me enough", or "I live in a quiet place"). Maybe some people start asking these questions because they haven't considered much about their asking? Perhaps they think that they are being sociable, and showing interest? However - when the questions are intrusive - then think of some answers ahead of time, or think of some topics to re-direct them.