I think you'd be surprised what even a little manufactured exposure can do. It doesn't need to be undercover. At almost every company I've worked at that asks for feedback I recommend some version of this. Some things I think you could learn in only a few hours at a Starbucks:

  * "Wow that machine is a pain in the ass to use"
  * "3 customers got angry at me because ____"
  * "Making ___ the way Jane showed me was much easier than the training"
  * "I hate it when customers pay using ____"