system
Given the following post, respond as if you're commenting on Reddit:
human
[General] When someone needs to draw blood why do they always cut the palm of their hand? Isn't that like the most inconvenient place to have a cut?

I mean really.
gpt
The act of giving blood is in part the "Life Energy" stored within the blood, but it's also the crippling of the self. You actually lose a little bit of your *soul* every time you use your own blood as a component in a spell, or ritual. And that is not to be done lightly. 

Honestly? You really don't need too, but it serves as a reminder to what you have done. And the pain is meant to remind you of the severity of your actions. It's a little sacrifice to keep things in perspective.