A friend of mine joked that a recent Windows update “downloaded the entire internet and then proceeded to install it”. The next day, I watched with horror as my computer restarted with the same Windows update...it took a similar amount of time (45 minutes to download, 30 minutes to install)

I would really like to know what it was downloading, and why it took so long. My entire windows partition is only 100GB, it would have been faster for me to back up my data, download a new ISO and install Windows from scratch than to just update it.