First, conservatives and liberals do tend to differ in terms of personality. This is a well-known, well-confirmed proposition in political psychology. Among the "big five" personality traits, two are significantly associated with ideological sympathies. "Conscientiousness" is pretty much what it sounds like. Wikipedia helpfully notes that, "Recently, conscientiousness has been broken down, further, into two 'aspects': orderliness and industriousness, the former which is associated with the desire to keep things organized and tidy and the latter which is associated more closely with productivity and work ethic."

Conscientiousness is positively associated with conservatism. The other politically-relevant personality trait, "openness to experience" is a bit harder to characterise, but "involves active imagination, aesthetic sensitivity, attentiveness to inner feelings, preference for variety, and intellectual curiosity." Openness is positively associated with liberalism. It's worth adding that one recent study found that another of the big five personality traits, "agreeableness", also relates to our ideological tendencies, but this was detected only when agreeableness was broken down into two different components: "compassion", which leans left, and "politeness", which leans right.