I also take pleasure in the so-called negative power in Grotjahn's work. That is I love his paintings for what they are not. Unlike much art of the past decade Grotjahn isn't simply working from a prescribed checklist of academically acceptable curator-approved 'isms' and twists.
As I approve of a youth that has something of the old man in him so I am no less pleased with an old man that has something of the youth. He that follows this rule may be old in body but can never be so in mind.