A bug reporting paradox: don't put in too much detail
Here's a paradox about bug reporting: while details are good, too much detail is bad (and by this I don't just mean too much verbosity).
Specifically, you should not go into too much detail about what is going on unless you are certain that you know what you're talking about and you're sure you're correct about it. By what is going on I don't mean symptoms (those are relatively easy, although tedious, to get right) but what happens when you do things like go digging in the source to narrow down where exactly the problem is.
The problem is that when you sound knowledgeable and sensible, it is very tempting for people to believe you; after all, it saves them time and effort and so on. But if you turn out to be in over your head and wrong, the result is that everyone wastes time (and people get irritated at you, which defeats one of the purposes of bug reports).
This doesn't mean that you shouldn't go digging at all, because going digging and being right about it is often the fast and best way to get an issue fixed.
(All of this goes double for patches, because it is easy to get them wrong in subtle ways if you don't understand the code. Even testing it yourself isn't really enough.)