People in their "Youth" experience the sense of not knowing which direction to really go to. They are confused whether going forward, left, right and backward is the right direction. And those scars in their faces symbolizes their pains while deciding.
@pledis_17#Left_n_Right
But ofcourse, there are different types of people during youth. People who are trying to go on first but there are also people who are still just lazing around waiting for the right time to go.
Seventeen in Left&Right wants to tell us that to "do your best but not sometimes"