When creating my characters, I tend to rely on my favorite past-time...people watching. Sometimes, my characters are random strangers I observed on a certain day. Others, and most often, I use characteristics of people I know. In other words, you may very well share a specific trait with a character, or perhaps read a conversation you recognize.
My main characters tend to have some form of a relationships, be it romantic, or purely platonic. I tend to use my own marriage when writing the 'romantic' aspects. But, the question really is, do opposites attract? My husband is a very laid back man. He rarely tells me no, and will eat anything I put in front of him. He couldn't care less if I wear makeup or designer clothes. Therefore, most of my males tend to be more laid back, and live to make their ladies happy.
I, on the other hand, tend to be a little high strung. I'm constantly full of energy, and anxious. I can hardly sit still more than thirty minutes at a time without getting restless (not a good trait for a writer). Therefore, my females tend to be high strung and energetic.
But, is this a normal phenomenon? Do attracts truly attract? I've seen many couples (both in my personal life and through general observations) who don't compliment each other's 'flaws'. Rather, they seem more like oil and water, bouncing painfully off each other, never melding or mixing, always pulling away from each other.