What are your favorite Polin changes from book to show?

Specifically, what are some dynamics/things in Colin and Pen's relationship in the show that they changed from the books? I'm mainly talking about their dynamic as a couple, but you can also talk about any changes they made regarding Colin and Pen as people individually.

Also, what does everyone think about the change that none of the Bridgerton family (besides Violet) clocks that Colin and Pen have a romance blossoming between them?