[Eastbound]

"We may still be reeling with denial, anger, bargaining, and depression, but you will never, ever have our acceptance."

I would suppose that the comma after the word, bargaining, would be proper, as the words are not related. But if they were related, like in 'anger and despair, you don't need the comma.

[Eastbound]

OoPS. I meant to say ‘bargaining and depression’ needs a comma because the words are not related in the sentence.