Daily things, Friends, Social life, ...
One of the local mosques here used to publish the prayer timetable for the whole year in HTML format. That was fine for me because I had the ability to add a bookmark to the current month to my N900 desktop.
In 2011, some brilliant person decided to publish them only in PDF. The idea itself is not that bad, I just lost the ability to add the bookmark to the desktop. Combine that with the not so great PDF reader for the N900 and my dislike for PDF files in general and you shall understand why I was really annoyed.