What prompted John Cerabino to cosplay as Gary Oak?

At this year's Anime Milwaukee, I had a chance to talk to John Cerabino, also known as "Moderately Okay Cosplay". As turns out, one of his many cosplay outfits was Gary Oak. I asked him why he chose that character, and what went into the costume:

On a side note, we're also looking for comments on the music of the twentieth Pokemon Movie, "I Choose You!". Here's some info on that: