Mr Know it all

or Mrs Know it all

We know them all, the people who always have something to say.

When you have a problem with, let's say, a new camera, they do not discuss the problem, but they ask you why on earth you could choose such!
Hey people, you not need to response, when you have nothing to add to the question!

When you have not understand the question, I think it is better to ask further, until you know what is meant, before you answer, instead of just pretending that you know it all.

As a good, wise, and wonderful man said.  When someone asks you a question, you not necessarily need to give a solution. It is already helpful when you listen, and truly understand the question.

So, maybe some of you know what I mean to say with this.  Let us see!