Kid A, 2000
Recently - so, only about twelve years later - I got it. I think, anyway. It's about OCD. Maybe this is an over-literal interpretation of the title, but I think I'm right. Thom Yorke disagrees apparently, but what does he know? He only wrote it. Maybe he was chanelling.
No, it's definitely about what it feels like inside to have OCD, even if Thommo doesn't realise it (and nor would I know really). It starts by imposing order on some random elements; this goes here, that goes there. "There are two colours in my head" - black and white, presumably - Thom sings. The real world, however, intrudes. The random elements return, the instrumentation starts to fracture, things are not in the right place any more. The echoes and distorted repeats threaten to overwhelm the voice, which sounds increasingly desperate. Order is only restored by a retreat into the womb-like security of your own head, with just the beating heart for company. Live (such as on I Might Be Wrong) this process is made explicit by the more extreme sampling and distorting of the musical elements. It's all very cool and not even spoiled live by the whooping morons attempting to clap along (honestly, ffs).