Been using my wonderful marking program today. Together with the snipping tool for the Tablet PC it makes quite a formidable device for grabbing bits of program displays and listings, annotating them and then dropping them into a customised web page for each student. I've had to put an embargo on "bright new ideas" (although I do write them down) because if I implemented them I'd never get any of the proper work done.

But when I use my programs I always find problems "round the edges". Sometimes the student files aren't quite right, or their programs get stuck, and then my program misbehaves and I've had to sort it out. I reckon that a programmer should spend around 20% of time solving the problem and then around 80% of the time handing all the ways that their solution could fail. Add on around 50% for testing and 20% for writing documentation and you get an understanding of why programmers are so busy. Or why some programs don't work as they should....