Yes, the east side. The west side, for the most part, is quite dry and therefore not suitable for coffee production.
Also, while butter is a direct product of milk cream, I, too, find the idea of stuffing butter into coffee quite repulsive.
Now, natural chocolate has a quite high content of fat (cocoa butter), and while at the first sight, a cup of hot cocoa with fat floating on top looks strange, it is oh so good once you try it.
Once you try that, you'll never go back to the stuff that is sold commercially as "hot cocoa"/"hot chocolate."
That crap has a higher content of sugar than actual chocolate!
Yuck!
As for adding alcohol, I personally find that Kahlua works quite fine in both coffee and chocolate. In small amounts, as it's rather sugary. There is coffee liquor produced in the same area as my coffee and chocolate, but it's more Baileys-like, so I'm not a fan of it.
For tea, the best additive is Peruvian (note: never Chilean) pisco, or, for a milder flavor, Bolivian singani.