There is probably some explanation, but in general, I find many CSS properties confusing and unintuitive: `color`, `text-align`, `position: absolute` vs `position: fixed` (absolute is still technically relative!), etc.
Everything is laid out on the page in a flow, according to DOM order. Think how a typewriter produces text on a page: top-down, left-to-right. This is the flow.
Absolute takes the element out of the flow while relative maintains it in the flow.
What isn't clear (even to many experts) is that certain properties change the layout model entirely and that text has its own "pushing" box that contributes to sizing.
Absolute takes the element out of the flow while relative maintains it in the flow.