I can really identify with this. A poor UI will drive user's thought processes. Kind of like the Sapir-Whorf hypothesis (http://en.wikipedia.org/wiki/Linguistic_relativity). When new users come into the organization, their thoughts are shaped by the program used to do the job.
Unfortunately at this stage no one seems to really know the business processes, and the software now dictates the process (even when incorrect). It's quite a struggle.