Question about tenses

I'm writing a short story for my class, and I'm not sure if this fragment is grammatically correct:

"The time of heavy thinking finally came, and there was a bottomless bag of things he wanted to ponder: his life, the people he had met, his goals and his dreams, what had been and what should have been, the right and wrong choices he had made, the successes and failures he had had."

Is this okay or should I replace past perfect with past simple here? Or do you have some other advice?