On one hand, we can be proud of the flesh that God made and take glory in it. We nurture it and keep it looking good as though it is who we are.
On the other hand, we can also be embarrassed about that same flesh that God made and provided us with, pitying ourselves as though it defines us.
Either way is vanity, and comes from not believing who we are as children of God.
For all that is in the world, the lust of the flesh and the lust of the eyes and the boastful pride of life, is not from the Father, but is from the world. -1 John 2:16