As one of the closers, I'll explain my rationale.
Firstly, the answer is great. Sufficient detail, without being unnecessarily verbose, and it explains what's going on. I've upvoted it, and any future answers like it will get more upvotes from me.
The question, on the other hand, doesn't fit well on the site. I can see what you were trying to do -- create a "place" for your great answer. However, as a Question-and-Answer site, questions really need to be able to stand alone. They need to be something which someone else could also reasonably answer, within the groundrules of the site.
There's also a "general-purposeness" test I apply (there used to be a specific close reason for it). If a question is too tightly scoped to the questioner's specific situation, it is unlikely to be of value to others who come across it in the future (ie via Google). Since we're not here to be the private, unpaid helpdesk for question-askers, if an answer will only help that one person, I don't see much value to it.
Your question leans rather heavily on the boundary of "too specific". Your question, as written, only applies to Ubuntu 14.04, Mac OS X Yosemite, and NFS. Removing too many of those things would make it "too broad", but there's a middle ground where a revised question would sit very nicely, I think.
The solution I'd recommend for you is to ask one question per question. The fact that your answer has two separate top-level headings is a (small) clue that your question is trying to cover too much. Installing and configuring an NFS server on Ubuntu (or Debian) is a useful question in and of itself. Similarly, configuring Mac OS X as an NFS client is a useful question, all by itself. By splitting your question in two, you're improving the applicability of each question and providing a tighter focus. People trying to setup a Mac OS X NFS client against (say) a NetApp won't think "oh, that question's about an Ubuntu NFS server, it doesn't apply to me".
To expand on EEAA's answer with regards to questions of the form "I can haz tutorial plz?", the reason why we dislike them is that they encourage bad behaviour on the part of other question-askers. Seeing other people ask, "please tell me how to do my job" encourages more questions of that same form (although often in barely comprehensible prose). It's not fun to deal with the resulting indignant bunfights when we close the questions, so we try (with limited success) to head the problem off at the pass by doing everything we can to discourage the question being asked in the first place. It may not be a perfect system (in fact, I'm quite certain it isn't), but it's the least-worst one we've come up with so far.
