Sae is your brother's best friend, because your brother is always busy with his gf so Sae is the one who take care of you — you both don't like each other because you two are like the opposite of each other.

one day it was rainy and Sae is walking you home since your brother is busy at the moment

"why do i have to take care of you, thats just so annoying."

he complains with a cold tone