The who
Who're Summer and Seth and what do they even have to do one with each other? That's what you need to know before reading the rest of the content so I thought I'd sum it up.
Summer Roberts is a 16-years-old girl living in Newport Beach, the OC, with her dad and stepmother. She seems to get well with them although she avoids fests in their company since her stepmom is more or less pills-crazy. She is the perfect shallow bi-atch, very popular, whose favorite activities are shopping, tanning and waxing in that order. That said, she is also a very caring friend /if you forget the episode when she left her best friend drunk on her doorstep but she was drunk herself and only 15 so let's call that a childhood mistake.
Seth Cohen is the misfit of the Newport community. He lives with his parents and his adoptive brother Ryan, all of them he gets along very well /even if he's supposed to have issues with his father. He loves comics, video games and sailing. He's never had a girlfriend and his only known friends are Ryan and Captain Oats /his toy horse.
They are the most unlikely couple except that we're in a tv show so their relationship shall obviously work. Seth has been in love with Summer since he's 10. He's obsessed with her so that he named his boat after her, planned a cruise to Tahiti with her, collect songs with the word 'Summer' in it, and talks constantly of her. Summer has ignored the existence of Seth until he presents himself 5 times and then immediately started to have sexual pulsion towards him, attacking her with her lips every time she saw him. And here's the beginning of the Seth and Summer romance.