I think it's time for a little levity don't you?
Once there was this columnist who had to write a column but he had a problem. He kept forgetting to use commas. He had already neglected to use two.
Do you see where the two commas are missing in what he's written so far?
To cheer himself up he went downstairs to his basement turned on a single dim light lowered the blinds sat down on the floor opened an old wooden box [optional serial comma] and dumped his comma collection onto the floor.
Wow he noted the previous sentence has a lot of missing commas! Not counting the serial or Oxford comma between "box" and "and" his column was now missing 10.
If you're reading his column on hard copy he suggests you mark it up (that makes 11). And if you need a quick review of comma rules before you read on he recommends you do as he did: Google "FAQ punctuation" (where you'll find this column with all 26 of its missing commas).
He knew that nonrestrictive clauses (or clauses that describe) do take commas and that restrictive clauses (or clauses that define) do not take commas so he would not have placed a comma after the word "columnist" and before the restrictive who-clause in the second sentence of his column (even if he had remembered to use commas). And now he was missing 13 (not counting the optional comma between "commas" and "and" in this paragraph).
Knowing that his readers (the few who were still reading his column) were choking over the words "nonrestrictive" and "restrictive" which he used in the previous paragraph he opened an envelope marked "Top Secret" and unfolded a musty sheet of yellowed paper where he read "Follow these instructions." (That makes 17, including two missing nonrestrictive commas before the words "which" and "where" in this paragraph.)