I'm not sure I follow how this works. I assumed that one could choose a mood for an individual post. I decided to try choosing one; nothing seemed to happen in the post (that was before you fixed it), but it did identify my mood at the top of my screen.
Once it was fixed, it turned up in the posts. So, evidently it works like everything else, where whatever mood is chosen shows up in all one's posts.
I had assumed that if one was posting in a thread about someone who died, for instance, one could use a sad mood, and for a happy birthday post there could be a happy one, etc. But, if the same thing shows throughout, then clearly that can't be done.