(spoilers)
I have zero interest in spas, so I will say that this episode turned out much better than I had anticipated. More than once, just when I thought I had the whole thing figured out, things went in a direction I did not anticipate.
First, Applejack is frequently too busy with chores to go to the spa with Rarity. With the rest of the Apple family apparently out of town, Twilight and Spike offer to handle one of these chores so Applejack can enjoy just one hour to relax, but both sides encounter problems.
At the spa, the line for the one thing Applejack wants becomes so long that she decides to find the problem (which turns out to be a leaky steam pipe) and fixes it herself, but all of that takes up the entire hour. Meanwhile, Twilight (rather predictably) insists on following the checklist word for word, despite how each step turns out weirder than the last.
Now comes the direction I had not expected. Applejack explains why she does each step on that checklist, and her friends make her realize just how pointless many of those tasks actually are, due to the underlying problems they solved had already been fixed. So then they move on to some other chores, and what basically happens is that while Applejack has been doing tasks one at a time, her friends demonstrate how much easier it is to get the whole sequence done in one move.
The message of this episode (old habits that are very time-consuming can be hard to break) does get me on a personal level, for I will confess that I still have certain habits to this day that do take up quite a bit of time. While not as problematic as Applejack's, I have already identified many of them and even taken a few steps for improvements. So it is this personal connection that gives me a rather favorable view of this episode.
(end spoilers)