Think about some great leaders that you know. Are they kind of an a-hole? Film Director Max Joseph noticed a trend in the industry where it seemed as though the more abrasive and cutthroat someone was, the more successful leader they were. After his own experiences directing a film, he decided to explore this topic and produced an entertaining and insightful documentary about what it takes to get to the top. If you've ever directed a film, video, or photoshoot, there are quite a few nuggets of inspiration in this short that might help you to become a better leader yourself on your next project. Warning, some language is NSFW.
The short answer is no, you don't have to be a dick to be a great leader, but it is one approach. You do need a vision, passion, and to be as resourceful and as motivated as possible. There are lots of good books quoted in this doc, and if you're into reading and self-development, one that I might specifically call out is "How to Win Friends and Influence People."
For those of you who lead projects of any discipline, do you find yourself being a respected, effective leader? What's your strategy?