Hubris is a common trait in villains because when people see an ideal they want to represent or support, they see it reflected in their morals and the examples of people in the past. It usually leads to being an educator or a political leader or someone in a pre existing field with the idea to change how something should work.

Villains are usually the same way, unless you have those small time villains who are just stealing to get by and feed the family. If they are the scheming type of villains, they likely have variables in their life or just simply arrogance to decide that their ideals and goals need to be realized via an unconventional route that completely disregards morals, whether that is terrorism, domination, assassination, etc. In order to get to a mindset that allows them to decide such methods are "right", they need a certain level of confidence and arrogance, which likely only builds as their plans progress.

Also, a lot of villains enjoy explaining their plans to heroes because in the end they are people. They may have a few servants whom they see as competent and intelligent, but they likely don't see them as equals or rivals. The hero, regardless of origin, if they made it all the way to the villain through their own means, is now a rival, an equal. So they feel the impulse and desire to tell them their plans, because they want their equals to revel in their genius.

The greatest villain I have come up with is a sovereign to got to his throne by legal means (read: killed his brothers and hastened his father's death), and surrounds himself with close allies that he either has something on or gained their loyalties well enough that he trusts them to a degree. In that group, everyone is intelligent and cunning in their own ways. He has two advisors that he admits are more of a schemer than he is, and they bounce ideas off of each other and brag to each other. Neither are the main villain, so they hardly see an opportunity to end up meeting any of the main villain's enemies. It allows the villain king to let free his petty desires from his arrogance to his advisors, and not leave himself any openings in crucial moments. Physically and in combat he is virtually Darth Maul, so he has covered the more physical routes to his defeat as well. Not the most powerful warrior in the world, but he is a legal head of state of a nation that is politically significant, and he is strong enough to fend off assassins. He is largely untouchable.

(Also you might want to ask /r/FantasyWriters, except as a writer instead of a god. There are actual authors there to advise you. I'm pretty sure I've seen similar threads there before.)