After multiple requests to do so, I hereby publicly present my Universal Theory of Musician Personality as it Relates to Primary Performance Register (UToMPaiRtPPR- catchy, right?): Stated simply, the higher in the musical register one sings or plays (soprano, flute, trumpet, violin, lead singer, etc.) is directly related to how uptight the person is, in their "natural state." Likewise, the lower one sings or plays (bass, bassoon, tuba, bass, bass guitar, etc.), the more mellow they are and the more likely they are to know the best place to find good beer. Or even half-way decent beer. Or just beer. This situation also tends to apply nicely at the micro-level within a section (think first trumpet vs. fourth trumpet). No doubt, there are exceptions to this, but those fall into "uptight for a bass trombone player" or "really cool for an oboist" categories. Nature/nurture? Cause/effect? Back pressure? Unclear. You're welcome. Note: Since the initial posting, I received many questions related to the treatment of pianists and harpists. My general feeling is that if they think of themselves as soloists, they lean towards the "upper" end of the scale and if they are collaborators, they trend beer-ward.
Russ Etters made this handy graphic to help illustrate the theory. So it's all science-y and stuff.