A Separate Peace
How we cite our quotes:
I was beginning to see that Phineas could get away with anything. I couldn't help envying him that a little, which was perfectly normal. There was no harm in envying even your best friend a little (2.20).
The more Gene justifies his feelings toward Phineas, the more we can see that he's still ashamed of his actions.
This time he wasn't going to get away with it. I could feel myself becoming unexpectedly excited at that (2.30).
This is a minor event – a small transgression at an afternoon tea – but it speaks volumes as to Gene's character. This is where we really start to see his resentment of Finny's seemingly easy success.
"You always win at sports." This "you" was collective. Everyone always won at sports. When you played a game you won, in the same way as when you sat down to a meal you ate it. It inevitably and naturally followed. Finny never permitted himself to realize that when you won they lost. That would have destroyed the perfect beauty which was sport. Nothing bad ever happened in sports; they were the absolute good (3.7).
Finny creates the Super Suicide Society as another form of sport, which ought to, according to his rules, be purely good. What Gene does by causing the accident is to turn the tree jump into a jealous perversion of that sport.