[quote=Krein]
Michael is partially justified for living a hard life under discrimination and doubt, as well as being the host of one temperamental god that goes nicely with Michael's own temper. Charlie just acts like a douche because of his daddy :p.
[/quote]

not entirely, he acts tough because he is part of a group of half-bloods who have to fear of retribution from the Olympians. his attitude is common among many warrior cultures in actual history, if you insulted a warrior from ancient times then it would almost always end in bloodshed. not to mention these cultures always trash talked about their rivals and enemies, so i view Charlie as having a more old fashion type of personality in that sense.