Does this 3 cups is of expresso, filtered, or the watery stuff common in USA?
If you're going to inadvertently dis' someone else's choice, make your intent known - i.e. point out that it's just your opinion. Don't give it that superiority-stance.
~64 mg caffeine / ounce in espresso
64 mg/ounce * 8 ounces * 3 = 1536 mg
From wikipedia: "Consumption of 1000–1500 mg per day is associated with a condition known as caffeinism."