Spirit of Harmony is used for a number of useful crafts in Mists of Pandaria, but as we all know, it is also Bind on Pickup, meaning your character has to actually farm every single one. There are many good spots for doing this, but there is also a way to be guaranteed a few each day, and it only takes about 5 minutes of your time!
Why you need Spirit of Harmony
This doesn't apply to all production professions, but for most it is benefitial to get as many Spirit of Harmony daily as you can. With Jewelcrafting every Spirit of Harmony allows you to craft an uncut Primal Diamond, which when cut will easily sell for 500 gold or more on most realms. Tailors need them to produce Imperial Silk. Leatherworkers can produce leg armor with them. And so on. All these items have in common that they are in high demand, and you can never really produce too much of them.
Farming Spirit of Harmony. Literally.
In Mists of Pandaria we get access to a farm of our very own. It is located in the Valley of Eternal Blossoms, in a little phased area that is unique for your character. Through a variety of quests, you will eventually get access to 16 farming nodes which daily can produce most cooking ingredients that grow in the earth, as well as a number of other useful items. One of these items is Mote of Harmony, and from your farm alone, you can get 16 of these each day. Meaning 1.6x Spirit of Harmony every single day! Given the potential profit of each, we're talking an extra 1000g or more daily profit here, or 30000g a month. Is that worth 5 minutes of your time?
If you haven't done the Tillers questlines, or lack reputation with them, you can't farm motes this way. You can't plant seeds for profession materials until hitting Revered with the Tillers, and you need to be Exalted in order to be able to unlock all 16 nodes. So if you haven't done it already, I suggest you start farming reputation with them! And don't worry, it's definitely worth it, no matter what your professions are!
To speed up the reputation grind, I recommend Zygor Guides. I'm using it myself, and love it. It's simply the best in-game resource you can get!
Now go out there and start farming! Literally!