Unless other specific, when answering questions the answer should be exactly what is needed and no more. This is probably a confusing statement. So, let’s look at some examples?
In each case, the answer calls for a specific set of criterion for an answer. In some cases, the question is closed, which means the answer is either Yes or No with no real obligation to give more*.
When reading a question, it is important to take note of all of the conditions of the question. Conditions are the individual parts that make up the whole. Therefore:
Do you think Star Wars is better than Star Trek because of the Force or because of the hyperdrive? Or do you think Star Trek is better because of transporter technology and warp drive and the lack of the Force? Please explain why one is better than the other.
In this case, there are compounded questions that require you to consider more than one part and then answer. A simple answer of:
Star Wars is better because of the Force
is insufficient to answer the question. You would need to spend more time thinking of the reasons and then proceed to explain based on your reasons and reasoning. As this is also an opinion question, your opinion is necessary in that you either like or dislike Star Wars or Star Trek and your reasoning behind why you like or dislike something.
* — Closed questions can be tricky in that some people ask closed questions, which really are simple answers of either this or that and not more. In this case, the question is still closed and you’re following a form of social convention in either acquiescing to more information or ignoring the implied requirement for more information.