That's also true of people who are too depressed and too angry, you just need to aim for specific organs. It's only not true of people who are too calm (phlegmatic), where I assume the thing to do is, I guess, use a bunch of cotton swabs or something. I can confirm that I wouldn't be calm if most of my phlegm was removed.
I don't really understand the actual "procedures" associated with humoral theory, so definitely talk to your local blood-letter before trying anything at home.
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