What's wrong with my Team Fortress 2?

I just downloaded a game from Steam called Team Fortress 2 because it was just announced free. I waited for 13 hours and finally the download was complete. Then the community toolbar thing popped up. (I use a mac) The game worked fine for the most part, then the game froze. I then restarted my mac and tried the game again. Again the community toolbar thing popped up before I launched the game. The screen turned black and the cursor went into that rainbow wheel of death and I waited for 10 minutes and nothing happened. I restarted my computer AGAIN and i tried to launch Team Fortress 2 again and still nothing happened. I'm not sure if the community toolbar thingy is affecting the game or something else is. Please help?