Lyric discussion by Ricesoup 

Cover art for Daydreaming lyrics by Radiohead

So, I agree with some of the inferences made about the video being symbolic of the experiences of life. However, I think the song itself is pointing out the fact that it's all in service to an illusionary experience or "daydream". The "dreamers" are the humans who are consumed by their ideologies (damage is done) and cannot correct course (no return/too late). The white room, to me, is likely meant to allude a hospital or point of entry into the world. In other words, the beginning of the "daydream" in which the process of learning to be human begins. The speaker believes that this process is corrupt but that it cannot be fixed (beyond me/beyond you). He is "just happy to serve". His song is a lamentation of the fact that he realizes he is in an illusion and is still playing his part in it.

My Interpretation

@Ricesoup the white room is a mental hospital. The Listener is insane. He doesn't know he's a dreamer. He may even be talking about other dreamers as if he's not one of them. But he is. He's broken.

The white room by the window is where he belongs.

The people serving is the staff at the mental hospital.

They're serving you.