Linux is moving beyond it geek origins, and its desktop environments are no longer struggling to catch up with its proprietary rivals. All the same, the priority remains how an application works, not how it looks.
Some users are automatically dismissive of eye-candy. Others favor a minimalist look to their interfaces. It's not that users are against aesthetics so much as they have inherited a ruthlessly practical outlook. Besides, aesthetics are associated with Windows and Macs as a triumph of marketing over substance. And in the last couple of years, associated with Unity and GNOME as the imposition of a small group's assumption on the entire user base.
Users may welcome a well-designed interface, so long as it doesn't slow down the system and has a reasonable selection of features. But, after having to settle for functionality while free software was developing, they still give it higher priority than mere looks.
When Windows users agree to the license, they agree (among other things) to Microsoft automatically updating the system and scanning for unlicensed software.
While Linux users have nothing against security -- being, if anything, far more security-conscious than Windows users -- the idea of changes being made to their system without their explicit approval strikes many of them as decidedly unsafe.
And as for accessing their systems for any other reason, or activating software before using it, forget it.
Any given Linux-based software is in a state of more or less constant development. For this reason, bugs are not unknown. However, when bugs do occur, the expectation is that they will be acknowledged and fixed as quickly as possible.
Most developers I know take this assumption very seriously. I have even known some to take personal time off work to spend the afternoon correcting a reported bug on an application or package for which they are responsible.
Linux users may start by being helpless to troubleshoot their system. But Linux has a long history of fostering a do-it-yourself attitude. Many applications, as well as large parts of the system, are configured in text files that can be easily edited from the root account.
Sometimes, of course, this tinkering can cause disasters, especially if backups of original configuration files aren't made. Still, after a year or two, many Linux users find themselves configuring their systems in ways that they wouldn't have imagined initially.
For many users, this attitude extends to a far greater user of the command line than is common with proprietary operating systems. Many Linux desktop applications are no more than shells for command line tools, and Linux's BASH shell is far more powerful and easier to use than anything found on Windows. Although you can still find Linux users who fear the command line, a surprising number are more or less comfortable with it.
In general, where Windows encourages passive users who turn to experts when anything goes wrong, Linux encourages users to get their hands dirty and to learn how to manage their systems for themselves.
These expectations can be summarized very simply: Linux users have a sense of ownership. Windows users are told in the license agreement they have bought only the right to use the software, not the software itself. They are used to thinking that they can do little to influence the manufacturers of their software, and to ceding their rights to do very ordinary things to the manufacturers.
But Linux users are in a more complex situation. Using licenses like the GNU General Public License, they are often restricted in how they can redistribute their software. But this restriction is irrelevant to most users.
Of course, much of this sense of autonomy is unconscious. It is absorbed far more than it is ever deliberately expressed. In fact, large numbers of Linux users dismiss the free software activists, the minority who do think deliberately about such matters, as fanatics. Yet in their daily computing, most of them demand and expect exactly those rights that free software licenses bestow.
New users, accustomed to more restrictive operating systems, can be slow to understand these rights. Yet, despite the growth in Linux over the last few years, even users brutalized by proprietary licenses soon expect the same rights over their software that they have over their clothes and car.