So far I give it to the missile save in "Hidden", it was one of the few times Clark didnt have a problem. I know he died, bu when he had his powers, he had no trouble doing it.
Every other time involves 5 minutes and a commercial break of him squirming next to some krytptonite.
Clark does everything with the same thought in mind: "I cant let anybody get hurt." So whether it's kryptonite or bullet he does it with the same meaning. So every deed he does is heroic
But he does it with the same intentions. He knows he can get hurt more ways then physically. Like whos_pete said, he sacrafices his love life with Lana and he also sacrafices someone finding out each time he uses his powers
Yes, but sacrificing his love for Lana isn't heroic. It's selfless yes, but not heroic. But also people fear death thats why they choose not to act. With Clark having powers, he doesn't necessarily feel all that. When he didn't have powers, and he knew he could die, he still tried to help.
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The only thing thats with you your whole life is complete and utter darkness.