short sleeve shirts vs. long sleeve? simple...short sleeve are cheaper...pilots are usually cheap.
as far as personalities...I agree with B2n2...many are a#$holes, or shall I say apu tailpipes?
and maybe your dad is, in the cockpit, how would I know?
Some pilots are dumb, some are super smart (yours truly), many tried being nice and it backfired on them.
don't change your personality, study hard and think and be good at flying planes...don't worry about what oxford thinks of you. many other places to learn how to fly!