What causes game to freeze?

What causes the game to completely freeze. The only way to get out of it too is by alt tabbing to create a new desktop, opening task manager and right clicking the game to end the process.

It's happens twice in the last few days now.

A badly behaved mod, or a new feature, that is getting stuck in a loop of some kind.

I am pretty sure it's some corrupt mods. There a few out there that don't like me for some reason. Recently my game is crashing a lot and connection is basically fucked. High pings for literally no reason. In 10 years of playing the game on and off and i've never experienced this.