I've always had this question but I didn't know the name for what I wanted to ask until just recently (figured it out while reading a tutorial for the Inform Interactive Fiction system).
When using commas in a list of things (see examples below) should there be a comma between the next-to-last item and the word "and"? I think it makes more sense this way (see examples below).
Example set 1:I like squirrels, cheese, and typographic design.
I like squirrels, cheese and typographic design.
To me, the second method doesn't separate the two items, or indicate a pause (and the average reader would pause between "and" and "typographic design" regardless of whether the comma was there or not, right?).
The separation makes things clearer, in my opinion:
Example set 2:I like squirrels, cheese, and mashed potatoes and gravy.
I like squirrels, cheese and mashed potatoes and gravy.
It gets worse when the item containing "and" isn't the last item:
Example set 3:I like squirrels, mashed potatoes and gravy, and cheese. I like squirrels, mashed potatoes and gravy and cheese. I like squirrels, mashed potatoes, and gravy and cheese.
In the second sentence in set 2, the terminal comma (is that even the right term for it?) is removed, and in the third sentence in set 2, it is re-inserted, but in the wrong place, drastically altering the meaning of the sentence. Read aloud, the sentences probably sound about the same, but I think I like the extra clarity added by the terminal comma, but see many texts in which it is omitted.
Is the terminal comma proper punctuation?