I started Minecraft for the first time yesterday and got to the launcher clicked play and got an Error message.

What I expected to happen was...:
I should hit play and Minecraft 1.8 should start.

What actually happened was...:
I hit play, it loads for a bit with the Mojang logo then shows me an error message. (See attachment)

Steps to Reproduce:
1. Make sure Minecraft 1.8 is running
2. Click Play
3. Wait