Back to Raymond's point, I had a customer just this week where our software was going really slow when saving their scanned images. I looked at the screen, saw they were using the B&W profile in our software and went hunting elsewhere (looking at SQL Server, etc). Turns out the crucial bit of information I got the next day was that barcodes on our forms weren't being read well two weeks prior, so instead of calling us and having it solved in 5 minutes they called the scanner manufacturer who sent out a guy a few days later. He went into our software and changed the profile called "B&W" to actually scan in greyscale - nice!
I then get the call a while later about things being slow (old XP machine with 512MB of RAM trying to scan 60+ pages of greyscale and process those images for barcodes and other identifying features). When I was told about the [scanner manufacturer] man and the barcode issue, which we'd seen at a dozen other clients I went into the TWAIN driver settings and disabled the "make my images look nice" mode since it's a well-known issue that the "improvement" is nice, except that it ruins barcodes (turns them into hollow rectangles). 5 minutes later they had a fast scanner and were reliably reading barcodes...
Rant over :) I can appreciate Raymond's frustration