I think because 4/5 is extrovert in CIX, it made them get closer easier since they can approach each other easily, and also most of the members are naturally caring and conscious of others, Their personality also helps introvert Jinyoung (btw I'm a bit like Jinyoung) to boost his confidence in approaching other people and also to be more loose (to not think too much of things), specially Byounggon (Remember chamele-Gon (>_