A/N: Takes place at the end of S01E20, "Obscura"
Lex had never particularly liked psychology. His interests tended more toward the harder sciences, with a detour through ancient history. That said, he was still a Luthor, and would probably be dead by now if he didn't have an intimate understanding of how people worked. Still, psychology had never been a hobby for Lex, even if it had always been a necessity.
Which is why Lex was somewhat surprised that evening to find himself pondering not the alien artifact his team had found out in that field, but the Kents and the concept of reciprocity.
It was, on the face of it, a simple enough thing. "Scratch my back, and I'll scratch yours," as Jonathan Kent might say. Or perhaps he wouldn't; it didn't really give the proper menacing aura. And given Mr. Kent's reaction every time Lex tried to offer a helping hand, he did seem to think reciprocity was something menacing. Lex could almost appreciate the supreme irony of such a fount of down-home wisdom so completely missing the point.
But whatever Jonathan Kent thought of it, menacing or not, it was likely he was wrong. Reciprocity was, after all, so much more elegant and pervasive than most people gave it credit for. Humans had an innate tendency to like those who like them, and likewise we hated those who hated us in turn. When people are kind to us, we are kind to them, and when they lie–
Give people what you will and they'll pay you back in kind. It was just human nature. Maybe, Lex thought amusedly as he played with the octagonal disk in his hands, it was alien nature too.
What he found funny, the same way he might find a knife in the back funny, was that that this phenomenon could be everywhere and in everyone, but it was only evil when a Luthor did it. He had to admire the consistency of their irrational distrust, if not the sentiment. (And Lex decidedly did NOT think of the way Mr. Kent got so angry at Lex being out in that field, or Clark's insistence that Lex leave the meteor shower and the idea of aliens alone because he promised Clark he would stop digging. Luthor's might not be obligated to keep their promises, but friends were, and the Luthor legacy could go to Hell as far as he was concerned.) He highly doubted anyone was going to accuse Chloe of using her feelings to manipulate Clark into liking her, but that didn't change the fact that Clark hadn't been interested in her until after he had found out about how she felt.
And really what was so bad about using reciprocity to get what you want? It was the golden rule after all, "Do unto others as you would have them do to you." If you wanted someone to be nice to you, then you should be nice to them, and if you wanted your blatant liar of a friend to share his secret with you, maybe you should open up and share a few of your own.
Before he could come to his senses and change his mind, Lex picked up the phone. He listened to the ringing and tried to ignore his father's voice in his head telling him that Luthor's always played things close to the chest and didn't let anything as ridiculous as sentiment trick them into giving up everything they knew.
"Kent residence," came a cheerful voice.
"Hello Clark."
"Hey Lex," Clark answered even brighter than before, if possible. It seemed Lex had been forgiven for his earlier transgression, even if he still wasn't sure what he had done wrong. "What's up?"
"Nothing important, I just wanted to ask if you would stop by the mansion next time you're free," Lex replied, fingers brushing over strange metal and unfamiliar symbols. "I have something I want to show you."