system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When the sun or moon is reflected on a body of water that has moving waves, the reflection appears as a ‘path’ leading towards you. Why doesn't it appear simply as an enlarged sun or moon due to it being ‘out of focus’ due to the waves?
gpt
Because you're essentially seeing a million little curved mirrors, not a big smeared fuzzy one. 

Take a hand mirror and stand under a ceiling light so you can see that light above you. Now pivot that mirror to the left and right, or up and down. Sometimes you'll see that light - it'll flash - and sometimes you won't. It's only when the mirror is at the perfect angle that you get that light's reflection. You could get the same effect if you had a bendable mirror instead, and bent it in a curve that included that light's reflection in your point of view.

Now visualize waves instead of a mirror. Small and medium waves are made largely of curved surfaces. (You get a point at the top they're generally big enough to break.) So what you have is a surface like this : 

~ 

but repeated over and over again. Those curves are still mirrors and the right parts of those curves can be at the right angle to you and the sun/moon to reflect the sunlight or moonlight toward your eye, in the same way that the mirror you held reflected the overhead light when at the right angle. 

And because the reflected sun or moon is very bright, even the tiniest of patches at the right angle amongst all of those waves sparkle and really shows up against the darker water around it that isn't that perfect angle. That huge contrast causes a series of sharply-defined specks rather than a large blurry spot.