Teach your desktop and screen saver the Craftsman philosophy. You hear me harken back to this credo again and again – "Have nothing in your home which is not beautiful or useful or both" – but remember that even for Discardians it applies not only to eliminating those things which don't meet that standard, but also to enhancing your surroundings with beauty and utility.
In 2005 I started actively using the principles of Getting Things Done and found a really great chart that summarized the whole approach. So handy! Did you know that on the Mac you can make your desktop pattern use a pdf file? Yep, that's right. My work desktop on my secondary screen (the laptop when it's plugged into a monitor) is now a constant reminder to keep focused on the right next action. (Turns out it was a good thing I saved that chart when I first saw it – I can't find it anywhere anymore).
Okay, useful. Check. What about beautiful?
I find favorite photos of friends and scenery to be a great way to let go of stress and energize myself and a little variety to be the spice of life, particularly in this regard. Did you know that the Mac allows you to set a desktop pattern that changes randomly every 15 minutes drawing from a folder of images? This is very pleasing on many levels, most notably that my background pattern on my primary screen provides new views out of my windowless cube. Best of all, utility still comes into play because the color changes at the edges of my screens under all my open windows remind me that 15 minutes have gone by and serve as a little nudge to ask myself if I'm focused on the right activities.
Check into the functionality available on your computer and see what you can do to provide small pleasures, especially at work.
If, unlike me, you actually do work at your desk with the computer idling, then your screen savers are another good place to provide yourself with images that give you a positive feeling. Whether it's beautiful vacation vistas or kids making silly faces or handy references, personalizing your virtual space will give you a lift.