every time i join a server my minecraft crashes

Put the summary of the bug you're having here
whenever i join a multiplayer server my minecraft crashes
What I expected to happen was...:
Describe what you thought should happen here
it would fix the next time i joined
What actually happened was...:
Describe what happened here
my minecraft crashed every time i joined a multiplayer server
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...