Post-series, I think that Ryou eventually does cut his hair. and just watch it fluff up with emotions as if he’s in a Miyazaki film XD

I guess the shedding of his long locks would be a symbol of him letting go of the past, a way of looking towards the future with higher hopes, and nothing was going to hold him back anymore.

 

Something similar to this, I think. XD

But, anyway, when he first gets his hair chopped off, Kaiba does keep staring at him. He had been wanting Ry to get a haircut for a while, but he didn’t know how far the kid was going to go with it, so… yeah. It’s a fairly dramatic change. 

(Source: twilight96.web.fc2.com)