Why Rob and Barry are both jerkholes.
Rob is the a-hole all of his ex-girlfriends claim he is. He never lets his present relationship stop him from getting involved in another relationship, but he agonizes over all of his breakups. He gets to play the field, but his girlfriend needs to stay devoted only to him. When he reflects on why the girl he screwed over the most told him why he was such a jerk, his defense only confirms it.
Barry, with his criticism of everyone else's musical tastes, proves that you do not have to be rich to be a snob. When you work in a record store, your job is to sell records and make customers happy. Not scare them away but telling them what you really think about their musical tastes. Who made him the authority on all things rock? I really wanted to jump into the movie and tell Barry to go screw himself.
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A dope trailer is no place for a kitty.