[You're making him think about stuff he'd rather forget, you know.]

I dunno? Like, we were friends first, and suddenly one day I realized I didn't want to be 'just friends' with her. It was probably after Kyoto...

[Oh whoops now he's getting sad, because he's remembering things now. How Shiemi rejected him, how she always gets around Yukio, how Yukio acts about it...]

...that's probably a bad way to look at it anyway, since it didn't work out.