Off-topic: “When I do X, Y happens. It shouldn't. Fix it.” (Even if you happen to know that the maintainer hangs around here, this is not a bug tracker.)
Off-topic: “When I do X, Y happens. It shouldn't. How can I fix the offending program?” (This is not a programming site, and even on a programming site, this is only ok if the bug has been narrowed down to a small piece of code that is included in the question.)
Off-topic: “When I do X, Y happens. It shouldn't. Has this bug been reported yet?” (This is not a search engine. That being said, it can be hard to find where to report a bug, but chat is more appropriate if you need help there, because it isn't easily transferable to other people.)
On-topic: “When I do X, Y happens. This is surprising because I expected Z. Why does Y happen?” (And if Y turns out to be a bug, so be it.)
On-topic: “When I do X, Y happens. This is obviously a bug [e.g. because it's a crash]. Given …, how can I work around it to do Z?” (The question should of course make it obvious why “upgrade to a version with the fix” is not a valid answer.)
On-topic: “When I do X, Y happens. This is obviously a bug [e.g. because it's a crash], but I don't have enough information to make a bug report/avoid running into it. How can I find out …?” (Where answers might be thing like “look at /this/log/file” or “activate this trace mode”.)
On-topic, but do check official channels first: “What's the impact of bug B on a system where …?”
On-topic, but do check official channels first: “How does this security exploit work?” (While Stack Exchange isn't really the place for this, we've had a few great answers.)
my system is not working properly, how can I fix it...
this did not feel right for me, therefore I started this discussion and got plenty of aspects to take into account on these regards. Especially about posting more detailed information in the question.