GREED
Eugene was always the people-person of the two of them. He, as a child, used to think that since the two of them looked exactly alike, Gene can make up for his lack of social skills. During family occasions, as a favor, he would ask Gene to go around and introduce himself as Oliver, so that he can skip the "I haven't seen you since you were this big!" part of the day. Martin can always tell the difference, but kept quiet and laughed at his sons' antics. Luella, in turn, would let their guests in on their little tricks and everyone would chuckle at Eugene's guilty grin.
As a result, Gene had become the family-twin. Oliver would participate from time-to-time, but Eugene was always the one who made an effort to bond with the crowd. They would never say it out loud, but Oliver always knew their family favored Gene over him.
He didn't blame them, nor despised Gene for it. It was a fact he accepted most of the time.
He had always wanted to be the favorite twin, though. It was something he had always known, yet never admitted to himself.
One time he and his twin made a card for Mothers' Day. It was Gene's idea, and by the time they were almost done with it, Gene had fallen asleep on the crafts table. Oliver took it upon himself to finish the whole thing hastily, and presented it to Luella, cleverly leaving out Gene's part in it. When he woke up, he told Gene he had given it to Luella on their behalf and she was very happy and grateful for the both of them.
Up until this day, he never told Gene he didn't tell their mother it was a team effort.
It was actually one of the pettiest things that kept him up at some nights.
A/N: Character experiment. :) Please bear with me.