If you've never seen user testing where users try to use your software, it's one of the most eye opening experiences a software engineer could have. I've seen a number of these tests at MS in early 00's when I worked there. It's as though the people using your software are from another planet, with a completely different set of rules in their head as to how programs should be used.

This kind of exposure tends to generate a lot of empathy towards the user, as well as to the demands of the designers and user experience specialists. It also helps engender the right kind of intuition as to the level of UX complexity and cognitive load non-engineer users are prepared to tolerate. And that level is very, very low indeed.