Having spent time in that world, it varies. There are people who have their ideas to improve the world, and know that politics is the path to doing them, who just suffer through the politicking part. There are a surprising number of shy introverts in politics- policy geeks who can talk to a camera but clam up around people they don't know, but you find those people in Congress, mostly in the House, where a campaign is mostly about direct mail pieces. Statewide usually requires a lot more razzle dazzle, but sometimes you get people like Michael Bennet in the Senate who get appointed to the seat from wonk world and just keep going.
And then there are some who are just in it for power and ego and see the unwashed masses as a thing they have to endure. I get the impression that certain florida politicians with constantly changing ideological positions who keep seeking higher and higher office fall into this category.
But yeah, there's a reason that most national level politicians seem like they need continuous human contact in order to survive. If you've ever seen Bill Clinton work a crowd in person, you'll know that it's basically the same as breathing to him. He can't live without it. To an introvert like me, it's just a totally foreign existence.