There are clear instances of over-punctuation and others of under-punctuation. In between it is a matter of style and preference. When in doubt, listening to the countours of how the sentence would be spoken can be a good guide, but not an infallible one. Sometimes I write something and a comma goes in and comes out because I cannot decide if it helps or hinders.
<Sometimes I write something and a comma goes in and comes out because I cannot decide if it helps or hinders.>
Isn't that just a matter of knowing the way you want to say something. In the above case, it seems you wouldn't have decided how to say a certain thing.