I *love* writing documentation for my code. Part of my development approach is what some calls it "document-driven development". It's part of my thought process. I put my thoughts as comments as I write code, and those comments ultimately become the documentation.
I *hate* looking-up documentation. Since I love writing it, I expect other people to document their code, especially if they expect other people to use it. I'm currently using Ruby, and the gems are notoriously lacking documentation. The "Documentation" page looks more like a README than a documentation. I'm used to MSDN/.Net/Javadoc documentation. Show me a list of all the classes and all the methods and their description and with some examples how to use them. Nothing consumes more of my time if I have pull out Google, type-in my question, and browsing through the web for a solution.