I worked at a TCBY one summer, back in high school. We sold both soft-serve and hand-scooped, as well as fountain sodas and cookies.
Little details can make all the difference in authentic research. We used to chop the candy bar toppings by hand in the back room (Snickers, reese's cups, etc...). We'd eat the balls of frozen cookie dough that were for our "fresh baked" cookies, which were baked in a tiny little convection oven in the back room. We'd take jugs of the liquid soft-serve mix from the freezer to the fridge to thaw overnight (both were big, walk-in's). Portion sizes are very specific by store, and we had to use a little scale until we could eyeball it correctly. We'd give our friends extra scoops of toppings, or charge a smaller cup size than they ordered.
My strongest memory, though, is of the scooped ice cream. There is a little tray in front of the freezer that fills with water and has a drain, and that's where we keep the scoops between scooping. The water was always cold. Every time I'd scoop, my wrist would press against the ice cream tub and get sticky stuff on my skin. Water would drip off the scoop, sometimes into other ice cream flavors, sometimes on the front of your shirt. But I always felt sticky in that store, and I washed my hands a lot.