I took a two or three day on-site intro to R class that my employer put together. Perhaps it was not a great class, but as a seasoned software developer familiar with a number of imperative and functional languages I was baffled by R. It felt like a bunch of little functions that had been developed by different people with no consistent framework, and thrown together in some kind of big wrapper. I know it's popular among statisticians and researchers, so I think a prerequsite must be a good fluency with statistics (I don't have that). Maybe it makes more sense if you think like a statistician. As a programmer I felt like nothing I learned about R contributed to developing an intuitive understanding of any of the rest of it.