Childhood is idolizing Superman
Adulthood is unironically realizing Lex Luthor is completely in the right

Seriously though memes aside if Superman were to suddenly appear in the real world you would all be absolutely terrified of such a person flying around with super-strength and laser vision. Lex's fear of Superman and desire to take him down is entirely understandable. The only reason we know for sure that Superman is and will always be good is because he's a fictional protagonist, but in real life we could never have that certainty, can you really say that you would be willing to trust some guy with those powers if he suddenly appeared in front of you? However good he might sincerely be, I'd be on the side of taking him down just in case.