Grenwulf's always been beyond stubborn. On top of that, he lacks patience. When a man like him fails to open a jar, he smashes the glass rather than rely on a cloth for a better grip.
In Grenwulf's mind, using that cloth is a weakness. In my mind, it's far better not to have your food covered in broken glass.
It's a shame, because I think he has the talent to be a good swordsman. But his foolish pride won't allow him to admit it.
This book was included in The Contest from the Creation Club