Lilflyboy is I think the best authority on this subject for current times (I doubt we haven't met, it's been a bit since I was there).
Personality does play a part but like anything a mixture of personalities will lead to a disagreement etc but I think has little to do with the professionalism of most pilots.
I am sure we have met/flown with people who would happily dance with their pants off to "twisting by the pool" on a table in a bar but when it comes to work switch their minds onto the job and focus on a safe op that makes their boss money.
Then you get the other end of the spectrum - over qualified guys of all ages who might be teetotalers but are a space cadet once then have a 182 and 4 sectors for the day.
An example of both extremes and by no way the norm of course.
I heard a story about a guy who worked oil rigs off Angola and he was saying there was a night when a good ole' southern boy was punching it out with big guy from Leeds while a Canadian was leaning on his shoulder and telling him how he paints his miniature Napoleon army soldiers for war games....
....And they're making dollars for their boss.