About personality, I would first focus on whether the person is a team player.
There are exceptions, but with the scale of today's application, most likely one has to work with others. A comparatively smart non-team player is the worst type of people you want on a team.
- If a person is not that smart, that's fine, there is always tasks for junior.
- If a person is smart and also a team player, great!
- if a person perceives himself as smart and not a team player. There is not much he can do, other than promoting stupid ideas by force.