A simple way to demonstrate that a movie character is an obnoxious misanthrope?

Yale Daily News - "Ghost Town" movie

One of the film’s most impressive successes is its portrayal of Pincus’ obnoxiousness toward almost any and all other human beings, which is not to downplay the also amazing demonstration of his awkwardness with the leading lady (a courting handicap best exemplified by “flirting” remarks referencing molar decay). In creating what is supposed to be such a repulsive character, the film walks a thin line between realistically portraying his misanthropy and making him into a Uncle Scrooge caricature. Luckily, the filmmakers achieve the former goal through such simple scenes as Pincus yelling “No!” at the poster-pushing, “global warming” propagandist (see the Activities Bazaar for details and sympathy).