Many HTML elements, like `div`s and `p`aragraphs, are "block-level" elements. By default, they take up the full width available and stack one on top of the other. You often don't need any special Tailwind classes for basic vertical stacking.
Item 3 (p tag)
The "Gotcha" is relevant here: for simple stacking as shown above, `flex flex-col` isn't strictly necessary because these are block elements which stack naturally. The next example shows when `flex flex-col` becomes useful.