But the point is that these feet were nowhere near the OP's head. The OP observed this from a distance.

I could certainly understand why the person in the front seat would be upset, but apparently it wasn't important to him/her to react to it (or the person simply didn't notice it).

My point is that there is huge difference in culture here (and from the pic the person with "the feet in the air" could very well be Indonesian which could explain it). What we wouldn't do in Europe or the US doesn't apply in other parts of the world.