One of my favorite examples for illustrating the absurdity of vainglory is Uncle Rico from Napoleon Dynamite. I love this clip (even though the audio's not great on this particular cut).
1. My vainglory is absurd.
2. My audience is Kip instead of God.
3. I'm delusional.
Ultimately vainglory is a real problem because the knowledge of God and knowledge of my self are tied together. A distorted focus on myself means a distorted focus on God. The more I have an inordinate desire for praise and recognition from others, the less I'll be focusing on bringing glory to God. I believe Napoleon has a theological word for my condition at that point: idiot!