I had thought I had managed to avoid completely avoid Notes in my career, then got a consulting gig about 15-16 years ago where I had to use it for a year or two. Even back then, we groused about having to use that antiquated pile instead of Outlook/Exchange.
It had a bad propensity to crash, to the point where I found this random utility called KillNotes that would shut down all the background processes still running when it would crash. If you didn’t have KillNotes, you’d have to reboot your computer to start Notes up again. KillNotes lived on my desktop for easy access, which says something about the quality (or lack thereof) of Notes code. And it was a fairly mature product even then, over 10 years old.
You haven’t used an antiquated pile of horse crap unless you’ve used IBM “PROFS,” their PRofessional OFfice System on a green and black terminal. There was about zero adoption at my company even though IT kept pushing it onto the company. We brought our own PCs into the company and used them with our own early Ethernet network built with our own cable and some early email system. Our CIO absolutely hated us, but our little experiment showed her we were right.