The first company I worked at was *all* Shadow IT. It was a small company which employed a large proportion of IT-savvy people (programmers, mostly), so they just relied upon whoever was nearest to sort out problems. I became the company's main IT person when they'd grown to a point where the old way simply wasn't working, and even then, I was still officially called a programmer and expected to spend 20% of my time programming; it was only when I ended the year having spent maybe 4% of my time doing the job I was supposedly paid for that they bit the bullet and made me full-time sysadmin.

Still, I sometimes miss those days. Yes, everything was a bit chaotic, but the one thing you could never call it is routine... 😉