generous - mean
hard-working - lazy outgoing - shy
easy-going - tense
cheerful - miserable
generous, unstinting - extravagant, immoderate
resolute, dogged - stubborn, obstinate
thrifty, frugal - stingy, parsimonious
diligent, industrious - work-obsessed, (a) workaholic (noun)
idealistic, principled - dogmatic, inflexible
shrewd, astute - cunning, sly
sober, serious - morose, sullen
witty, pithy - brusque, terse
tolerant, open-minded - unprincipled, unscrupulous
chatty, talkative - verbose, garrulous