I completely forgot that I had done this a long time ago but I hadn’t had to add a new calendar to my Google Calendars in a while.
The problem is, when you add a new Google Calendar, it shows up as a “Delegate” on OSX’s Calendar application. And that really suck’s UI wise because it’s a a completely different section. This makes it visually, as well as functionally, hard to see all your calendars and where they live.
Then I remembered this:
https://calendar.google.com/calendar/syncselect
If you go there, and log in, you can decide which calendars are going to show up as proper calendars on OSX’s Calendar application. Awesome.