If you are making a user interface for a high stress, high throughput situation, where the users are not trained to use your stuff, it would be nice if:

1. When I press on the first button to get started, you don't put up a progress/loading spinny saying "loading". Pre cache the entire UI or at least the first and second pages.
2. When the process of doing whatever it is I have to do is done, you did not then put up 2 pages of loading/finishing before indicating me I can move on in life / the next person who uses the terminal won't get my data (at least in theory, anyway).
3. When you offer controls for modifying hardware, you do not have both virtual and physical buttons and only the virtual buttons work.