Light moves along straight lines... Got it.
So if the light from that faraway star is traveling in a straight line, and that beam is, considering the distaces involved, at best one or two photons "wide", why, when I move six feet or so to my left, can I still see the star? IOW, why aren't there "dark" areas between the beams of starlight, where the stars "disappear"?
I will try to address 2 points here:
1) Light does not necessarily move by rectilinear (straight line) propagation. diffraction is one example. If you also consider general-relativity, then due to the curvature of space-time between 2 massive bodies, light will have to follow a curved path, known as a geodesic in transit.
2) The light from a star is not 1 beam wide, in fact, it has complete angular distribution from a celestial horizon to another. If you can't see a star at night, it may be due to its excessive dimness or due to it being beyond the horizon (notwithstanding atmospheric conditions). This very large angular distribution of its radiations allows you to see a star (don't forget that a star is in fact a sphere, not a point source of light).
There, in fact can be, and thus are, dark areas which causes the light to disappear.
Feynman explains this in the link; The punch line is at 4:20. But I doubt you can understand it without looking the whole series of these lectures. This must be one reason why the stars are twinkling (or scintillating)
Of course one problem is that your eyes' diameter is too big to be able to "see" these dark areas completely. The other is that these are all present in various colours.
