The people that use this site have some of the worst grammar ever. It is apparent when you look at series and lists. Here is what the average user will write: Jack, David and Carl are all stupid idiots. What's wrong with this sentence? Please submit your answers before reading ahead.

If you submitted the following: Oxford comma; then you are correct. People on this site forgot about the first grade, where you learn that a list keeps its commas until the "and". Here is how the sentence should look: Jack, David, and Carl are all stupid idiots.