It did a lot right and honestly modern Microsoft could stand to learn from some of the UX decisions, but using it for general use in 2018 is insane; there are absolutely massive security problems because it's not being updated and since it hasn't been updated with support for newer development frameworks, a lot of applications no longer support it. Pretty much all of the major browsers stopped supporting it quite a while ago, meaning if you use it for internet use, you're insecure both at the browser level and the OS level. That's really, really dangerous.