Like you're drawing one night, and you're thinking, wow this is good. I like this I should post this.

Then the next morning, you're like "shit I don't think my drawing was as good as I thought it was last night, I'm pretty sure it actually looks terrible, and I showed it to people fuck there's no taking that back"

I've never had a hangover or even been drunk, but I imagine that's the same feeling of shame and regret you feel the next morning