“in a mood” or “in the mood”?

Could someone explain to me the difference between these two phrases (if there’s any at all)

According to Cambridge Online Dictionary

• to be in the mood means to feel like doing something
  I am not really in the mood for shopping.
• to be in a mood means to be not friendly to other people
  Ignore him – he is in a mood.

And is there a phrase: It just goes on my mood (with a context: it depends on my mood)? I watched an interview with Hailey Baldwin the other day and she was talking about her everyday outfits, saying that the pick of the outfit goes on her mood.
Thanks in advance!