The next mark of knowledge: not clinging to the things the senses enjoy. Whatever pleases the eyes, ears, tongue, nose, or skin — not getting trapped by it. And the absence of the feeling that says 'I am great, I know everything.'
Alongside these, Krishna mentions something clear-eyed: seeing the suffering and imperfection woven into birth, death, old age, and disease. This is not pessimism. It is honest observation — seeing the nature of worldly existence exactly as it is, without dressing it up.