Yea coffee can be bright/light bodied/mild, tends to have more tea like qualities. Fruity notes and more acidity, African, and most South American coffees tend to be more like this. Where as coffee from Indonesia tend to be dark/full bodied/low acidity and have a more earthy taste. These are just simple examples, but there are plenty of in betweens as well.
As pretensions as it may sound I recommend the pour over method with freshly ground beans from a clean coffee grinder if your going to really pick up on nuances between each variety (and individual coffee roaster). This and time, coffee is not unlike other food/alcohol even noise music, you have to develop a palate just like you develop an ear.
Regarding decafe, I always assumed the chemical process to remove the caffeine would alter the flavor and therefore I never partook. I stopped drinking and never understood why some move to a non alcoholic beer, but that's just personal preference
