I like the red, blue, yellow, orange and green, and purple flowers.
I like the red, blue, yellow, orange and green and purple flowers.
The point is that these sentences are identical except for one missing comma. That missing comma changes the meaning of the sentence. In the first one I like a variety of flowers including a type that are orange and green. In the second sentence the meaning is hard to determine. Do I like a variety of flowers including a type that have three colors in them (orange, green, and purple)? Or did I substitute the word and for a comma? The first sentence is straight-up solid. Why insert ambiguity into it?