What I expected to happen was...:
I expected Minecraft to launch normally. It seemed to install just fine.
What actually happened was...:
A blurry Minecraft logo popped up in my dock, and after about a minute of my computer being completely frozen and the game hanging on the Mojang screen, it finally closed itself and went back to the launcher.
Steps to Reproduce:
1. Install the newest version of the launcher
2. Pick the newest snapshot
3. Launch on Mac OS X 10.7.5
And in the console of the launcher you will have a lot of data, please add this to your ticket 🙂