Q: Sierra, a big mistake

I liked the idea of being able to use Siri on my Mac so I upgraded to Sierra. Big Mistake. My "Send Later" app in Mail no longer worked and my Quickbooks no longer worked. These are two features that I use daily and can't live without and getting them to work again required costly upgrades. Within 5 minutes I was restoring my old operating system from Time Machine. Now everything is back to normal and working fine. Looks like I'll be staying with Yosemite for the long haul.