Why does plucking nose hair cause tears in the eyes? It's not a particularly sad or painful thing to pluck a few nose hairs, but it's common for the tear ducts to wet up when doing this. I would like to know the physiological reason for the correlation, how/why are the tear ducts and nose hairs related in the human body?

Although I'm not sure, here's a working theory. The tear collection ducts feed into the nose. That's why when you cry you have a runny nose. When you pluck nose hairs you irritate the nasal mucosa, so that causes a reflex which attempts to flush out whatever might be causing a problem.