on Writing Forward:
For such a little punctuation mark, the comma causes an awful lot of confusion.
Some writers are too liberal with commas, sprinkling them about like nuts on an ice cream sundae. Other writers hoard their commas and avoid using them whenever possible.
Why are these punctuation marks so widely misused? Why are we, collectively, so inconsistent about where we place them? One style guide says use them, another says don’t use them. Even the experts can’t agree!
But there are some rules about comma usage that we can all observe and agree on.