Your wikilink doesn't work. And, as stated on wikipedia, they perform "acts generally deemed "heroic," but will do so with methods, manners, or intentions that may not be heroic." Heroism is not so much about effectiveness as it is about the courage, nobility and self-sacrifice that they exhibit (see
merriam-webster). Thus an anti-hero would be someone who is cowardly, lowly and selfish who just happens to perform heroic feats every now and again, generally in between extended non-heroic feats. While Arthur Dent may not be the most heroic of heros, generally his intentions are good and he tries his best.
