When I switched to the Mac several years ago, the only big concern was access to PC games. But, there is dual booting, and there are virtual solutions, so I jumped in and never looked back. These days more and more games are coming out with support for the Mac on day one. But, I still find myself getting excited for a new game, only to be totally disappointed when I see that it is PC only.
"Just suck it up and run windows."
My solution used to be exactly that. But, now I'm taking a different approach. I don't buy games that do not support the operating systems I use. I do not support developers that do not provide software for my platform. It is that easy and simple. Sure, I would like to play Space Engineers or Fable Anniversary, but they are not available on OS X. So just get on with your life already. :)
The best way to influence a company's behavior is with money. Don't buy it or do buy it. The choice you make will help them to make decisions going forward. Now I know I'm in a minority on this, and I know that my one purchase won't make a huge difference. But, it's what I can do. Oh, I also do not download the game illegally. Don't be that guy.
Mac Games on Steam