yes: we only see light if we're looking directly at the source or if it's reflected off something.
there's nothing in empty space -- you don't see any reflected light in 99.xxx% of the sky. the moon, the planets, and passing satellites ((when you, the object reflecting sunlight, and the sun are oriented such that you're within the cone of the reflected light)) are exceptions, being reflective objects in space.
why isn't the sky filled with starlight all the time, if the majority of vectors, in every direction, intersect the location of some star?
a few reasons:
• there is a lot of interstellar dust in space. it absorbs a lot of starlight.
• stars are very very far away. objects appear smaller and dimmer with distance, making the vast majority of them too small and not luminous enough for the threshold of human eyesight, even at night.
• brighter lights 'wash out' dimmer ones. hence the sun is ((usually)) the only visible star in the sky during the day, and the further you are away from light pollution, the darker the sky is, and the more stars you can see. the same effect works when two stars are close to each other ((apparently close, angularly, from your perspective - not necessarily close in mean spatial proximity)) the dimmer one is 'washed out' - this is why it's hard to see stars near the moon, and the same is true for dimmer stars near bright ones.
• light travels at a finite speed, and space is vast, and being stretched out. the universe has a finite age, and stars a finite age much smaller than the universe. most stars are simply so far away, and so young, that light from them cannot have yet reached us.
