Wonsik is the type of person that falls for strangers easily in passing; chipper cashiers, kind waiters with cute smiles, attentive baristas, but something about the softly singing boy in the leather jacket makes all the butterflies in his belly come to life.
Taekwoon on the other hand, comes off a little more cold, a little reserved. He often thinks any affection he reads toward him is just him projecting his own feelings on the actions of others, and tends to shy away from getting close to people for fear of being misunderstood. Wonsik though can see through him, and that both thrills and terrifies Taekwoon.
Or; in which Leo is a quiet, short-tempered, introvert while Ravi is a bright, friendly, busybody. Both are mutually pining but too plagued with anxiety to do anything about it.