I think it is to be expected to a certain extent. At times, it can feel kind of ridiculous to ask certain questions (e.g. tell me about a time when...), but the questions still need to be asked. Other times, I will ask an intentionally open ended question expecting the interviewee to take it in whatever direction they want to, only to have them fumble over the ambiguity of the question.
In essence, the interviewer likely has a set of criteria through which they will evaluate the interviewee. Any question asked will likely be an attempt to probe one of those criteria. Say that I were to ask you about a time that you have worked in a team. You can be pretty damn well sure that "teamwork" is one of those criteria. Thus my advice would be to keep in mind what the question is probably evaluating, and to realize that you have an opportunity to make a strong impression. Fumbling over the question / avoiding the question is really a missed opportunity.
In addition, some interviews will be pretty rigid in their duration. In those instances, long rambling answers may actually prevent your interviewer from asking questions that probe other facets of your application.