He is an actor of details, always pays attention to the smallest traits his character could have and executes them in a wonderful way. Take Saikou no Rikon for example, didn't we all love Hamasaki's quirkiness? Also he makes those awkward scenes in jdramas feel totally okay and natural, which makes one feel more empathetic towards the characters. Plus the fact that his hair is so...unique! <3 <3 
I have only watched him in Mahoro Ekimae and Saiko no Rikon but he looks so different in both of them.He sure is a versatile actor.