And also every now and then I need to read a science paper in PDF format - somehow they still haven't figure out how to make accessible formulas in Latex-generated PDFs, so I'd have to use an OCR called InftyReader to OCR this PDF to get the formulas.
In my experience the worst offenders are drivers for printers and scanners. Every time my printer runs out of ink on my computer it'll show me a dialog, that my screenreader doesn't recognize at all. So by the presence of empty window I'll have to deduce that it's running out of ink. Scanner driver is completely inaccessible, so I had to get a linux box just to use my scanner - at least all the command-line tools are accessible.