I don't know if this line is strictly from the Donner movie or not but Jor-El says that one of the things Kal would do was inspire others to "join him in the sun". A successful Superman does exactly that. If and when an opportunity to hang his tights comes along, he would have achieved all he was meant to do if others can step up and take the mantle as he steps aside (and they do). He is not supposed to do it all alone, all of the time or risk the world falling apart because it grew too dependent on him to always solve its problems. It seems wrong to me to deny Superman a chance at normalcy even if it's for a moment just because of what he can do and has always done when the occasion called for it, which is all the time.

Lets be real, being Superman is a heavy burden and because of the man that he is, he carries that with aplomb. I can imagine the relief he'd feel for having to not carry the weight of the world on his shoulders when relieved of his abilities. Does that mean Clark is selfish for having those kinds of feelings? Hardly because we all have them at some point or another. It would be selfish if he intentionally turned deaf to every cry for help when none would come or blind to a villain decimating a city in front of his eyes and there was no one to save the day but him. I don't think that's the message that this book is conveying. I don't see them writing him like that even unintentionally.