Game crashes out of nowhere in servers/ loading screens freeze while loading.

Basically what's been going on is, that when i'm playing in a server randomly it just crashes all was fine when i got on the server and it was asking to download a texture pack so i did and that same loading bar now appears everytime i join how can i remove the texture or stop that?

Loading Screen Freezing~

There's not much to this one but sometimes the loading screen just freezes out of nowhere and it's really annoying how do i stop that? Or fix? -Rachel_Heart