Most people - even the overwhelming majority of programmers - would say that the main activity of a software developer is "writing source code". But this is a (though quite understandable) misconception - and if you take a look at the available figures on the issue or if you - as a software professional - are honest to yourself, the misconception immediately turns out to be an enormous one.

This is a great piece on maintenance and writing code being the easiest/least important part of software development.