I've noticed how similar my family is to Julia's family, which is perfect for me to better relate to Julia. During the slowing, Julia's mom was preparing more, while her dad wasn't as worried.(Our dads both like peanut butter.) Julia's mom was more concerned with if the clock time would really work, and if society would fall apart, while her dad thought it would. Sylvia didn't like clock time and said she would follow the sun's time, or real time. Gabby was just edgy and gave herself a tattoo of the sun and moon, and talks about a real-time community that she heard about from her internet boyfriend. At the very end of chapter 16, Julia saw her dad kissing Sylvia at Sylvia's house, which I saw coming, but maybe not with Sylvia.
One thing the book mentioned was a plan for billionaires to colonize Mars. I think it's a bit late to do this, since setting up a (self-sufficient) colony on Mars would take quite a bit of time. It also has had other things that I always found interesting, such as, if you look at earth 100 light years away, you would see earth 100 years in the past. It also adds more story than just the main conflict, such as Julia's friendship with Hanna.