Oh Mama, Where's My Comma? [State of the Art]

I was taught in no uncertain terms that a list of words was separated by commas. If a comma did not appear between two words, then they were to be read as collective equals, both together and inseparable. So we have a list such as: French toast, ham and eggs, and coffee. The ham and eggs are to be reasoned as one ensemble, served together, such that one without the other would be a huge mistake.