Today my co-worker noticed that when adding a decimal place to a progress indicator leads to the impression that the program is running faster than without. (i.e. instead of 1,2
Showing details (such as the names of files being copied in an installation process) can often make things seem like they're going faster because there's constant, noticeable activity (as opposed to a slowly-creeping progress bar).
If your algorithm is such that it generates a list of results, and you have some way of displaying results as they're generated (as opposed to all at once at the end), do so - the sooner the user has something else to look at besides a spinner, the better.