its cause they are having fun doing it, not everybody has to take it extremely seriously. they arent worried about stomping their switch 10 in their comp run, "training" all day. they just wanna relax and have fun. not that all snowboarders are fun happy people and every skier thinks they are training for the super bowl, but most the time its pretty accurate.
from an outside perspective, when you watch the skiers in a park and snowboarders, the skiers are all dressed either like simon dumont, or fucking t wall, they all either are spinning to win trying to show everyone up and be the best skier on the mountain, or they are all thugged out trying to afterbang their shitty tricks. we all look like a bunch of clones, trying super hard to look cool.
then you see the snowboarders and they are all fucking around havin fun, dressed in their own way, and usually could care less about showing up the next guy.
again its not always like this, but its more true than not.