see: す - imagine if it were written from bottom to top. The placement of the 'straight' part of the vertical line and the placement of the 'curl' would be opposite (especially if you're using a brush instead of a pen). This is similar to the lowercase English 'a' or 'u' written bottom to top - especially if using cursive.
or see: お
the last 'dash' in the top right is a retouching of the paper after the curl on the bottom right. Imagine a swirl that starts in top middle, swings around on the bottom left, swings around on the bottom right, lifts off the paper, and then touches back down briefly in the top right. If you're hand-writing, that little landing dot can be huge, tiny, or even conjoined, but to be legible it's generally visually a continuation of the lower stroke. If you just copied the letter without any concept of stroke, it would be difficult to read because you'd be looking for that swirl. Imagine the dot on a lowercase 'i' - it's supposed to be directly above the stroke for your brain to render it as an 'i' vs an 'l'. It's why when written out you can distinguish 'il' and lt' even though they're quite similar if drawn literally, quickly.
An example of stroke order vs stroke direction is more apparent when you need good proportions. Kanji like 風 or 看 are really hard to 'draw' with good square proportions if you don't stroke them in a particular order. Kind of like trying to draw a face by starting with the nostrils, then doing the eyebrows, and ending with the outline of the face - it's tough.
Interestingly, the Japanese hiragana letters are really designed to be written with a brush from top to bottom. The letters flow from one to the next really nicely when written from top to bottom, and are actually much harder to write properly when written left to right. See: す - き - の. They're much more natural to write top to bottom, and keep going down rather than from a left to right (which is also indicated by stroke order - the horizontal bars on the letters above are written before the downstrokes).