This is stupid, but also required hours and hours of my time. I was testing session handling in nodejs, and couldn't get it working. I made the assumption that it was because the package was complicated, new, and might be difficult to work with. The answer is actually much more straightforward than that. Also, I'm stupid.
The problem turned out to be related to how my computer works at night, when I close the laptop-lid. You see, I was testing this on an ubuntu-install running through Parallels. When I close my laptop for the night, it goes to sleep, and so-too does the clock in Parallels.
So it turns out, my ubuntu-install is about 7 days behind. What does this mean when you're trying to use sessions/cookies that expire after an hour? Well, the cookies disappear right away, and can't be seen by your browser.