A shelf does not become more useful every time we place something on it.
There is a point at which another object makes the others harder to see. The same thing happens to a day. An appointment fills the last available hour, and suddenly the hours around it feel smaller too.
Leaving space asks us to trust something we cannot yet name. The empty afternoon may produce nothing we can show another person. It may simply allow an old question to return in a different voice.
At a desk, this can be as modest as clearing a place beside the page. In a conversation, it can be the few seconds before we answer.
We make room, and then discover what room was needed for.