His voice,to me, is completely capable of capturing every human emotion. What I mean by that is that you can sort of feel his attitude through his songs. Not many artists can go from hard rock in one instant and powerballad the next, but Koshi pulls it off like a Pro. (Also the credit I give to UVERworld's Takuya) Koshi is so energetic on the stage and that just adds so much to the performance. Especially love the outfits he appears in. It just adds that much more.
Also, when Koshi ballads, as in Yuube Crying, Alone and Calling. It almost feels as though he is the song. It's that good
I also agree with the potato chip remark. The world would be a better place if more math teachers became singers. I mean, who could've foretold the success.