Anyone who's in advertising--or any other professions, really--owes it to himself or herself to read Desmond Morris' classic book of anthropology "The Nature of Happiness." You can buy it here, though I suspect you can find a pdf of it online and download it for free.
(Of course, this being 2016 I feel compelled to say that downloading a document is not the same as reading a document. Reading requires those things that are in shortest order today. Time and will. You have to allocate time to actually spend with it, and you have to have the will to abjure distractions--like Facebook, IMs or even blogs like this one.)
We have this saccharine notion in our world that happiness is a beach somewhere with untold dollars in unknown bank accounts with unfading lissomeness at our sides.
The truth of the matter is happiness is less accomplishment (at least if you abide by Morris) and more pursuit. It's the chase, not the kill.
Sometimes the pursuit in creating work is more satisfying than its creation.
Or maybe not.
In any event, something to think about on a rainy Tuesday.