As to why, my only guess is sadistic pleasure.

I am taking a certain amount of sadistic pleasure in this.

Her sadistic pleasures had been known to make their lives hell.

The sadistic pleasure, not only of hurting someone, but destroying this innocent woman.

It was whispered, too, that he got sadistic pleasure from slicing the enemy.

The officials, the suit says, failed to protect him and took sadistic pleasure in his victimization.

Praktis climbed up behind him, his expression one of sadistic pleasure.

Nick took a small sadistic pleasure in the Mate's obvious dismay.

She was clearly losing her mind or just taking sadistic pleasure in watching me lose mine.

That he would not perform for her sadistic pleasures.