Eric Raymond has a written a great rant on the usability problems of many Open Source programs out there, using his trouble configuring CUPS as a specific example. Now, hmm... why does this seem familiar? Oh yeah, because I spent nearly a year trying to get a similar setup working, and still haven't been able to do so. CUPS/IPP sucks.
Read the full rant. A must read for for any FOSS users and/or developers.