Okay, this is getting perhaps a bit off topic, as it is about writing in general, but it's something I thought about on occasion and it just popped back into my mind.
The problem is that Clark is invulnerable and doesn't need much sleep compared to a human, so he should have pointed that out. When he accepted Lois's argument about his needing sleep for work without even disagreeing with her, his offer looked like it was motivated by reluctant courtesy instead of genuine concern. In effect, that made Clark an unreliable narrator. He thought he was making a genuine offer, but based on the other information at our disposal, we assume that he was fooling himself.
The big issue here is whether you write how someone "real" would perceive his or her environment, or whether it is a full account of everything one needs to tell the reader to bring a certain point across. And for instance, the reasoning "I don't need sleep and stuff", that's not something I'd usually think about unless you first check whether or not you would be able and willing to help instead of just offering. It would perhaps make it even more calculating
instead of selfless. An undercurrent of "feeling it just was right thing to do" now that's a different matter all together
I understand perfectly from where this need for the characters to express themselves comes from, given how the reader must be made to emote, but at the same time, too much insight just seems forced to
me and unrealistic if I actually think about it instead of just go with the flow. After all, as I said before, IMHO people do not think this much when they react to a situation. It's different when lying around and staring at the ceiling, but while the action is happening, at least for me, there is not so much introspection going on as just going with what feels right.

But then, I'm not a professional writer, so
Hope this makes sense.
/hands thread back.
Michael