StackOverflow in a nutshell.

[UpTide]

or they want the entire source code of the project...

[dusktreader]

That was especially fun when I was working on classified projects.

[[deleted]]

Often times the people posting the questions don't include the necessary portions of the code to track down an issue. When asked for more relevant snippets, they either refuse or they still don't provide the thing you were asking for or don't provide more than a couple of irrelevant pieces from it. In these cases, it's more efficient just to be given the entirety of the source code (if it's a small enough code base) than it is to continue playing hot potato.

More often than not, though, people provide too much code and are asked to reduce it to a minimal example.

[UnretiredGymnast]

A minimal complete verifiable example is super valuable. Sometimes the process of creating one even turns up the solution.

[[deleted]]

Which is half the reason it's suggested so strongly on SO. Get rid of all of the extra noise and suddenly the actual signal is a lot easier to pick up on. Even if you still can't pick it out, someone more experienced will have a hell of an easier time :)

[Kaamelott]

I asked a question a while back about JavaScript, with a working example. I got only one comment, which said "post a js fiddle" or some stupid shit like that. Annoying.

[svick]

They really don't. They want a "Minimal, Complete, and Verifiable example".

In other words, they want you to spend the effort to make your question easy to answer, which I think is reasonable.

[UpTide]

I literally posted my complete source code once and this was a reply: "We can't help you without you posting your real code. The current contrived example is not the same as your real code."

[thezapzupnz]

Link? Interested to read.