The space between notes gives each sound a chance to remain itself.

Without gaps, everything runs together into a single texture. The silence around a note is what lets you hear it as a note rather than as part of a wash, which is why rests get written down as carefully as sounds. The same holds for speech, for rooms, for days. Definition depends on the empty parts.

Look at a stretch of your week with no space in it, where one thing starts as the last one ends. Put a real gap between two of them, even ten minutes. You will remember both more clearly for having let each one finish.