Any interaction that happens too fast crashes the game. I'm serious about any. Loading the client, updating and clicking play, clicking the store icon, adding bots, constantly crashes when connecting to chat, spells sometimes don't level when you click them the first time, switching from masteries to runes, talking while in Queue, post game crashes.
Unrelated but: pando media booster likes to load itself about 8 times and I can't end the process for some odd reason, sound does glitch and makes my speakers pop, any internet radio will slow down while playing LoL (literally the speed of the sound, not the browser or media player). It's not my hardware, and it only happens while playing LoL specifically.
I started out fine, but it happens all the time now. I've completely given up playing ranked because I wait about twice as much as I play due to crashes.
I can and will reproduce every single one of these. It's irritating and I'm about to rip my brain out.