Like repels like? 

What kind of illogical rule is that? 

Nevertheless, Lee Taemin believes in it.

Lee Taemin also believes that he is the best, the smartest, the absolute unmatchable. And when he gets an attitude from someone, he makes sure they can't sit on a toilet seat without shuddering when they think of him. That's how savage he thinks he is. He also believes that despite being a freshman, he is everything but. So he sees no problem waging a war against a senior who happens to be his roommate. 

Taemin thinks Choi Minho is a stuck up idiot, surrounded by money, bathing, breathing, eating, ting in it. He doesn't care one bit of his disgustingly expensive belongings, or his handsome face, though he gives him the credit for being born with that face and such an ugly heart, or his height because—well, s like him will die first when the sky falls anyway. He also realises that he has started smiling a bit too much, sure that his smile can and will, hopefully, give Choi Minho diabetes. He does not forget to always keep a pen-knife by his head-stand because a man gets urges when their roommate is the son of an even menacingly rich-looking politician+businessman. He is sure that he would be doing their opposition-party a favour, hah. 

He realises a bit too sooner that he hates Choi Minho's expensive guts and that he will, by the grace of God, one day be selling them after mutilating his dead body. 

Choi Minho is a senior, never shared anything except for Oxygen before getting told that he had to share the entirety of his dorm-room with a scrawny brat going by the name of Lee Taemin. First of all, what do poor people have an attitude for? Is it the taped earphones he is carrying? Or the ragged looking travel-bag he was so proudly dragging inside his room alongside the swaying flat-? Anyhow, he isn't a man of words, meaning bent to suit him such that he did not like conversing, specially to people who couldn't even afford lenses and have to carry spectacles behind which they try to hide their incapable, poor-looking eyes. So Minho decides one thing, that he is going to make college-life living hell for him.