Notes was very much a product of Lotus Development, a weird enclave that was nominally IBM but that made absolutely certain you knew that they were not IBM, a bunch of very booksmart people with very little street smarts and strong opinions on how things should work, leading to software that was full of super-clever hacks, starting with the batshit crazy login prompt (you'll know what I'm talking about if you've used it) and going downhill from there. And since all the focus was on adding super-clever features no-one ever paid much attention to the boring stuff like making it work reliably.

For former Notes users, there's https://www.cs.auckland.ac.nz/~pgut001/misc/notespotting.pdf to remind you what you left behind.