"AREXX was a lot of fun to play with"
AREXX was an utter revelation to me at the time and what I missed most about the Amiga. It seems to have taken YEARS for other OS to get even close to what AREXX could do.
I remember building some quite complex scripts using PoVRay + image processing + anim to automate raytraced animation construction that took a week or more to generate and build, using Parnet with two Amigas working on separate frames.