Zico is the type to throw his whole self into everything he does. When he loves someone, he does a LOT. He's very earnest, and this is made clear through the mass numbers of other idols and staff members that consider him a friend. 

He's focused on doing everything to the very fullest, sometimes he can come off as harsh or fake. He's also very much a perfectionist and workaholic. Personality wise he seems cold and distant as first but once you get to know he seems to care deeply about the small things in life. You can say he has a ocd complex,  where everything has to be perfect for him.