Unlike tea, coffee has a strong, assertive taste to it. I always add a splash of half-and-half and the coffee still comes thru loud and clear. At my local in-store Starbucks the other day, after requesting my usual hot coffee with cream, I asked the clerk what percentage of customers order plain coffee vs. their elaborate coffee-ish dessert drinks. She said maybe 10% order regular coffee. By far the diabetes-inducing concoctions are more popular. In fact, as I waited for my coffee, another customer stepped up and asked if she could please have more caramel squirted into her gigantic domed cup. The clerk was happy to oblige.
Starbucks uses beans that have been over-roasted. A properly roasted Colombian requires no addition, even in a French press.