Artistic Production or Personal Happiness: Which is More Important?

    I don't want anyone to be turned off by the sensational title of this post-- by no means am I asserting that the correlation between happiness and the quality of the art one makes is applicable to everyone. Certainly, there have been many happy writers and artists over the past thousands of years (although, come to think of it, I am having a difficult time thinking of any-- Sappho, perhaps? That's probably a cop-out because we don't know enough about her to make any assertions. Is it something about artists, or is no one truly happy in the first place?), but with the recent passing of David Foster Wallace the topic of artists and mood disorders has become hotly contested once again. It's a topic that's particularly pertinent in my life right now, and I was interested to see it come up in a Jezebel post today.
    If the video, from a documentary on Yoko Ono, isn't working, I can sum up the most important part of the whole thing: Camille Paglia (an author and professor at UArts in Philadelphia), makes the assertion that Yoko Ono discouraged John Lennon from practicing and using English humor, and says that "crushed his originality [...] He may have been a happier person with Yoko, but he was a lesser artist." This brings up the question of what is more important-- John's (or any artist's) happiness, or the quality of the work that they produce? Supposing that being happier brings about work that is lesser in quality, or in originality (which I have personally found is true), do artists owe it to themselves to be happy even if this means that their work suffers? I know that, for me, the quality of my work affects my happiness-- if I am producing good work, my mood is improved and I feel like a productive, contributing member of society. But in order to produce good work, I generally need to be in an "abnormal" mood. I say abnormal in terms of what is considered to be a stable mood-- I don't necessarily need to be depressed, but I cannot simply be content. No good work ever came out of being content. In order to write I have to be overemotional, or overly contemplative, or unstable in one way or another that may generally be harmful to my non-artistic being. I'm afraid, however, if I try to correct this in order to make my life outside of my art better, will my art suffer?