Nauru [wiki] is the world's smallest island nation, the smallest independent republic, and the only republic in the world without an official capital. Nauru only has one significant source of income: phosphates from thousands of years' worth of guano or bird droppings.
We may have the same friends. The same ones who take NyQuil when they're not really sick, just to help them sleep. So they're taking it for the diphenhydramine (Benadryl), which is much more cheaply purchased alone and as a generic. DayQuil is dextromethorphan, acetaminophen, and phenylephrine.
Stop taking DayQuil and ask a doctor if you experience: Nervousness, dizziness or sleeplessness. Symptoms that get worse or last more than 5 days in children or 7 days in adults. Fever that gets worse or lasts more than 3 days. Redness or swelling. Cough that comes back with a headache that lasts or a rash.