Like most thinking primates, I am sometimes baffled by my own behavior and reactions. As a result, I generally take an interest in research that explains otherwise puzzling behavior, particularly research involving subconscious influences. One type of study examines the effect of small, perhaps seemingly inconsequential, external events that prime people to behave in a certain way. The technical term for this is behavioral priming, and all sorts of fascinating results have been offered in recent decades. People who have been exposed to words associated with old age walk more slowly when leaving the psychology lab than those who have not, for example, and people who were asked to hold a warm drink as part of a lab experiment judged others more favorably than people who were handed a cold drink.
However, this work has been encountering problems lately, chiefly because it is hard to replicate, as described in this article by Tom Bartlett in the Chronicle of Higher Education. (You might also find an earlier article by Bartlett about the reproducibility of psychological research interesting.) Thus, the answer to the question in the title is that the jury is still out. Stay tuned.