Standing in a train station as a Shinkansen roars through without stopping was one of the most exhilarating things I've experienced. Worth the trip to Japan just for that alone.
Unlike in (most?) stations in Japan, there are no gates between platforms and track. I was standing maybe two-three meters away. (Took a step back initially out of fear of aerodynamic effects.) Damn, that was impressive! The roar, ground shaking, and how fast it was gone.
On a later ICE trip over that track, I observed that the train was doing 200 km/h at that point. ICEs can go 250-300 or so (on suitable tracks, which aren't many) based on model.
I personally think Caltrain still ranks well in terms of an impressive experience watching it pass.
Generalising to any shinkansen line. To experience this effect, you'd need to take a sub-express train (still very fast) to/from a station where the fastest train doesn't stop.