Quickcast is GREAT, I wish more people knew about it
I started using it just a few days ago, and I find that I hit so many more skillshots and am able to do things noticeably faster with it. I'm so glad I finally switched from regular click-to-cast. I just clicked the arrow under my Q by accident, and I noticed it wasn't showing the indicator anymore when I casted it. I looked in my settings to see if I had accidentally changed something, and that's when I knew I had accidently, luckily turned on quick cast. I think Riot should make things like this more easy to find out about. I'm still experimenting with Attack Move, and I wish there was a tutorial for things like this.