I always complain about how hard it is to relate to Clark because he ought to feel things differently as an alien who thinks like a human

I love authors who manage to come up with creative little details in which Clark is different from humans. The problem is to find the balance: in all the ways that really count, Clark is surprisingly human. I think it's a testimony to the Kents' dissembling skills that they managed to treat him as if he really *was* a human and consequently he became one.