With all things being equal, I think people want to deal with someone they know and like. And that’s probably true even if all the other factors aren’t equal.
There are lots of reasons to be nice and to maintain a good reputation. If you happen to lose your achievements or position, you’ll meet a lot of the same people on your way down, who you met on the way up. And people are more likely to share information and opportunities with you and your “brand” if they like it.
It’s even true in a peculiar environment like Hollywood that, as a place, has a reputation for insincerity and shallowness. Here’s what got me thinking about how important your reputation is: I saw this link on kottke.org to advice that director Steve Soderbergh gives to film students… one of the things I stress, in addition to learning your craft, is how you behave as a person. For the most part, our lives are about telling stories. So I ask them, “What are the stories you want people to tell about you?” Because at a certain point, your ability to get a job could turn on the stories people tell about you.