The data was stored in a really inefficient way and so the operation took a stupidly long time. I decided to add a progress bar so that people don't think the app is busted (which they occasionally did). Turned out, much of the time spent was on the server's end, so I couldn't track the majority of the "progress".
I had already put effort into the bar, so I replaced the "real" progress tracking with a script that randomly incremented the progress. I tweaked some heuristics until it roughly matched the amount of time the server tended to take but was random enough to not be super obvious.
After the progress bar launched, someone from the warehouse actually walked up and thanked me for the progress bar.
Of course, that's all fun and games. Weird psychological manipulation in e-commerce is horrible.