While he does occasionally help his brother Stefan and the main characters, Damon's overall actions are driven by self-interest and a desire for revenge. He frequently puts the characters in danger, often deliberately, and his motives are often shrouded in mystery.
However, it's important to remember that the concept of "bad guy" in *The Vampire Diaries* is often nuanced. Damon's actions can be seen as a product of his own trauma and difficult past. While he is the primary antagonist in Season 1, his motivations and complexities create a more layered and compelling villain than a simple "bad guy".