when i was logging in, (i tried several times.) it kept giving me a crash report each time i tried logging in. please help!

Put the summary of the bug you're having here

What I expected to happen was...: to play game
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...log in minecraft
3. ...press play