I was in lobby, the client was suddenly not responding.
I wanted to take a screenshot for riot support.
So I opened Snap tool, the client crashed everything so Snap tool was not responding too.
I tried Alt+F4, couldn't close it. I tried opening Task Manager to force close the client, Task manager became... not responding.
And then Windows explorer crashed.
Long story short, I had to restart my PC.
Nice client. 10/10