There is a cool paper out (Casasanto et al., Journal of Experimental Psychology: General. Vol 138(3), Aug 2009, page 351) where scientists tested whether people who are right- or left-handed have any biases towards objects that lie closer to their stronger hand. They set up some experiments asking volunteers to express their emotions associated with different photographs of people, places and objects, which were placed to the centre, or slightly to the right or left of the viewer. "Right- and left-handers implicitly associated positive valence more strongly with the side of space on which they could act more fluently with their dominant hands". Interestingly people made up lots of reasons as to why they thought that particular images were better, suggesting that they thought that they had reasoned it out and chosen the best option, but in fact the choice had been already made for them depending on their handedness.
It's been seen before in some older studies (e.g. Nisbett et al., Psychological Review. Vol 84(3), Mar 1977, page 231) where very similar but essentially indistinguishable items (such as clothes, electrical items, household objects etc.) were put on the right or left of viewers, and they were asked to carefully reason out which one they like best. Almost all of the participants chose the items on the right, but they gave a variety of complicated reasons as to why they had chosen the better item.
This shows that we are totally unconscious of why we do a lot of things, and are pretty good at convincing to ourselves that we have made a reasoned logical choice, when in fact we have just taken the route that was pre-determined by something deep and uncontrollable to do with our individual physiology. It's much more comforting to think that we are carving our own destiny, but maybe even the things that we like, the jobs we want, the people we think we are similar to, are all chosen a priori, and we make up comforting a posteriori logic to convince ourselves that we are our own masters.
It might be interesting to remember these things the next time we try to work out why some music sounds good (maybe we think it sounds exciting but actually the record was displayed at the right of the shop), or why we fall in love with a particular person (maybe they have mannerisms or often wear some colour which resonates strongly with our bodies, but of course we'll put it down to some profound mutual attraction).