Sometimes the first piece of data you need to gather is what the bug actually is. Often users file bug reports that have insufficient data. For example, let's say a user files the bug, "When I load the page, the web server doesn't return anything."
That's not sufficient information. What page did they try to load? What do they mean by "doesn't return anything?" Is it just a white page? You might assume that's what the user meant, but very often your assumptions will be incorrect. The less experienced your user is as a programmer or computer technician, the less well they will be able to express specifically what happened without you questioning them. In these cases, unless it's an emergency, the first thing that I do is just send the user back specific requests to clarify their bug report, and leave it at that until they respond. I don't look into it at all until they clarify things.
If I did go off and try to solve the problem before I understood it fully, I could be wasting...