For me happiness is the general on average state i'm in. My moods and feelings are very immediate - i can literally be singing on top of the world one minute and 30 seconds later feel as Dee describes. I irritate myself that i have such extremes of emotion - they are not quirks they are real feelings.
My hub and i have an incredibly analytical relationship - which is a bit exhausting sometimes - can be getting on brilliantly for ages and then a couple of days of not so well can lead to massive - state of the marriage discussions.
I do try to keep perspective when i'm feeling low - and think about the on average feelings over the last few weeks. Thinking about it for this thread though i only do that about my marriage and not the rest of my life - will try to get the same perspective on that!
Think that we can be happy in different areas of our lives - for instance over the last few years have been very happy on balance in my marriage, unhappy but then happy in my work because i've changed the things that made me unhappy and mainly unhappy about my weight. However after having therapy i feel much much happier in myself, my self esteem is far greater, my relationships with my family make me happier now that i have learnt how to deal with them and i really feel that i have grown as a person which definitely makes me happy!
(Sitting in my sunny kitchen with the kids still asleep reading this post to my hub as he's stiding about in his undies having him anxious to point out to you all how i'm very happy since i met him has made me very happy!)