When I'm trying to evaluate/install/manage software I sometimes feel like the software companies really don't care about my pain. They apparently think nothing of publishing pages of pre-installation notes followed by an installation with a myriad of painstaking steps that must be followed precisely or else you end up with an irrcoverable mess.
Now, sometimes they can get away with it when their products are popular enough that end users demand them -- like the Blackberry server.
But, companies that make less visible software should be careful. For example, Symantec's Corporate Antivirus product has a few notorious issues (failed uninstall cleanup, Outlook plugin issues) that aren't deal-killers in themselves. But, when an IT department looks to compare antivirus products, the idea of not having to deal with these problems can sound pretty appealing.
So, if you write software, keep in mind that end users aren't the only ones that have to use it. If you are causing the admins pain, you're opening the door for your competitors.