Adam-Troy Castro has a post up called “Writers: The Long-Term Benefits of Not Being An Ass,” which I encourage you to read, with the awareness that the advice has works equally as well when you substitute any other profession for “Writer” (or indeed, you can also substitute “human” and it works just as well).
Also, let me just second nearly all of what Adam-Troy is saying there. Folks, the fact is that people’s tolerance for working with complete assholes is pretty low. In the field of writing, in my experience, being an asshole is generally neither here nor there in terms of how an audience sees you (they’re focused on your output, not your personality), but it has a lot to do with how much slack those who have to work with you will cut you. And when no one wants to work with you, it makes it harder for your audience to find you.
And yes, if you sell millions of books, then you probably get to be as big of an asshole as you want to be and people still have to put up with you. But not many people sell that much. The list probably doesn’t include you (sorry. It doesn’t include me, either). It’s been interesting recently to watch writers who sell relatively little who have nevertheless decided being a complete asshole to other people in the industry was a winning move. They are either extraordinarily confident they will never be dropped by their current publisher (which is not a smart thing to assume when you sell relatively little), or they hope self-publishing will save them (also not smart).
(Or they’re simply convinced that it’s not them who’s an asshole, it’s everyone else. In the latter case, well, you can believe that, but if everyone else outside your tightly-sealed little group disagrees with you, then you still have a problem.)
Or, and this has been suggested to me before, there’s the theory that being a complete asshole is a marketing strategy to build an audience. My thought on this is, well, okay, but the sort of person who gets off on watching you be an asshole is probably an asshole themselves. And while I suppose that an asshole’s money spends just as well as anyone else’s, I’d still be uncomfortable actively cultivating that particular market. Again, generally your audience doesn’t care about your personality, but if you make being an asshole a selling point, to the particular market of assholes, then that’s the market you’ll be stuck with, you know? Then you’ll always have to be an asshole. And, you know. I can be an asshole just like anyone else. But I try to limit the total time I am one. It’s tiring. I can’t imagine having to do it all the time.
So, yes. Listen to Adam-Troy. Try to be a decent person, to the people you work with and even the people you don’t; Remember how you treat people on the way up is how they treat you on the way down; Maybe you can be an asshole if you sell millions, but you probably don’t and even if you do, you should still try not to be one. People remember. And people talk. And people choose who they want to do business with, and who they want to help.