If you're SLF with a fairly good idea of separations, and you find yourself down the back of VS19 having done your best to impress your companion with the details of how all this flying stuff works, and she points out of the window on approach to SFO and says "Why's that so close, then?", and you've never actually flown a parallel approach before, and for a good few minutes all that happens is that the other a/c gently drifts towards you... well, you learn to keep your mouth shut.
R