Put the summary of the bug you're having here

I open my minecraft launcher, I hit "play" and it starts loading the little green bar at the bottom starts filling up and then the window disappears, and then comes back with a crash report.
I can't think of what is causing it.
Since the last time I've played I have updated my Graphics software.
I was also trying to make a resource pack since the last time, I left the unfinished resource pack file selected in minecraft I don't know if that could do anything either

What I expected to happen was...:
Describe what you thought should happen here
The miecraft launcher would launch the game
What actually happened was...:
Describe what happened here
After I hit the "play" button the game crashes. It doesn't even get to the main menu
Steps to Reproduce:
1. I have no idea. All I do is press "play" and it crashes.... ...