Minecraft client keeps crashing (Exception in world tick)

Put the summary of the bug you're having here

What I expected to happen was...:
I joined a Minecraft multiplayer server and was playing it for about 5 min.

What actually happened was...:
But then suddenly (It happened a few times before) my client just closed while the launcher was still working

Steps to Reproduce:
1. Join a server
2. Play for a while
3. Minecraft crashes