I find the Uncanny Valley effect fascinating. It’s amazing how much little detail there has to be. Things like the fact that the pupils are at a fixed dilation, rather than changing and focusing like they should. The sub-surface scattering is just a tiny, TINY bit off, the jaw doesn’t appear to be rigged for side-to-side motion. The elasticity of the skin is uniform in areas where it shouldn’t be and the hair doesn’t have the fractional inertia and springiness that real hair, even at that short length, would have.

Of course, the human brain’s configured for looking at human faces. You’re not going to easily fool a machine stress-tested for that purpose by millennia of evolution.

Personally, I reckon games designers should never stop striving for realism, but we need to accept that it’s going to be a long time before we get there. Guys like me, who are just starting out, had better stay well clear of the valley in the beginning. Caricature’s easier, for a start, and it’s amazing how well-received some very non-human looking characters can be.