This piece on rap lyrics is very well done. It breaks down how (some of) the artists actually do put time and thought into what they are rapping, even if the audience can never tell what they are saying.
Many of the rhyme schemes in this video I had never even heard of. Some of them are so complicated that they require a lot of brain activity to wrap your head around, let alone create. Then there is the fact that a lot of rap artists never graduated from school (just saying), and that makes their talents even more impressive.
Granted this video does outline the rhyming of some of the greatest lyricists of all time and there are certainly a ton of mainstream artists who would probably be confused by this video themselves. Still, a great watch.