S4E8 observation
I really love the implication in this scene that the reason Eugene was able to understand Charles is because Sazz understood Charles and that came through in the script she wrote. It’s incredibly sweet, but also kind of heartbreaking when you take a step back.
Nobody else in the room knew what was happening. Of course, I can't blame them, they've never seen Charles act like this before, but it is very indicative of what most people who have seen him like this would have thought; it's nonsensical. That kind of dismissive perspective is almost certainly what built his belief that he needs to suppress his emotions, that yelling or even violence would be better than acting weird. I can imagine he heard a lot of “use your words” and was told to stop throwing a tantrum. But it was never a tantrum. Just because he wasn't able to literally say something doesn’t mean he wasn't trying to communicate in a very real way, and none of the people who shamed or dismissed Charles over the years bothered to get to know him well enough to find that out.
Then Sazz came along and for maybe the first time, Charles had someone in his life who didn’t just take his differences at face value. Instead of judging, she listened and looked deeper. It's because of that that she was able to understand him, and as we see in this scene, if others do the same(and they should), they can too.