I am thinking that Kryptonians are like Vulcans. Vulcans have emotions, but they are taught from a very young age to supress them.

It sounds like Kal does have emotions. He can't understand what is happening to him when Lois smiles or laughs, but it's obvious that something is going on inside of him.

Perry: (To Lois) Honey, this could be greatest story since Superman came to town. By-the-by, where is that husband of yours?
--Faster Than a Speeding Vixon