I think the key question that needs to be addressed is do you want your players to hate the villain or your characters? If the players themselves find the villain depraved, they'll end up finding reasons why their characters should go after them. For example, I have a player that absolutely loves animals. Regardless of the character they play, if you mention harming an innocent beast of any variety their character will intercede whether it's the villain or even the party. So as much as I dislike meta solutions, ethical contortion can be a huge factor for players even subconsciously. When you say "Thog the Barbarian hates orcs, there's an orc over there" the players might get excited to be extroverted but they won't be terribly motivated.
The next thing you have to consider is how powerful they are without making the players think the plot device keeps cranking in their favor. The villain needs to be capable of his nefarious schemes, but it shouldn't just be a case of "Baron von Evil is here so we're getting worked over". If they are connected, then you whisper the name of the core villain they never find. If they are physically powerful, leave just enough survivors to keep the players on the trail but make it vicious enough that they might hesitate to take the villain head on. If they are a manipulative character, make sure to have a diverse network of NPC's so that the players can't easily see the moles just because they're at the forefront.
The players need to be able to take a victory that they value even if the villain still gets what they want. As long as the players are making smart choices, keep rewarding them because it has to keep the party interested and not avoiding an inevitable beatdown for whichever venue they choose to contend. After all "Almost got'em" is a great spur.
Lastly, don't make your villain a cartoon. If they're insane and/or have some strong quirks that go outside of societal norms, please play them but do not make them so outrageous it's hard to take them as an individual person. In the comments someone said "kicking puppies and torching orphanages" and it reminded me that while these are unforgivable actions, the players have no stake in these nameless actions and the villain has no motivation to do them with just these descriptions anyway. Formula that strong leaves a bad taste in players' mouths.