Board Thread:General Discussion/@comment-2059440-20160506190434/@comment-1969141-20160508220237

No matter how understandable their motives and how sympathetically they are portrayed, I for one would sum things up saying that a villain comes with three ingredients, so to speak.

A conflict (which is the common point with antagonist, though the conflict with villains tend to be significantly higher) + a threat of varying scale and gravity + Something at stake (the hero having something personal to gain in addition to lifting the threat. The latter two being more or less linked.