The Stoics have this practice of imagining loss in order to become accustomed to it and be less attached to these temporary things. You start by imagining that the loss of small things, and then move on to imagining larger losses like the death of a loved one. Seneca writes in his Moral Essays:

He robs present ills of their power who has perceived their coming beforehand.

and Epictetus advises in Discourses:

This is what you ought to practise from morning till evening. Begin with the smallest, the most vulnerable things, like a pot, or a cup, and then advance to a tunic, a paltry dog, a mere horse, a bit of land; next yourself, your body and its limbs, your children, wife, brothers. Look about on every side and cast these things away from you. Purify your judgements, lest something not your own have become fastened to you, or grown together with you, and cause you pain when it is torn loose.

http://puffin.creighton.edu/phil/Stephens/OSAP%20Epictetus%20on%20Stoic%20Love.htm

You might think that this kind of meditation is depressing. I think it enhances my appreciation of what's in my life, and thus contributes to my happiness. Reflecting on loss–or even non-existence–helps me appreciate how things and people have influenced me.

Tangential story applying this to my life:

Actually, keeping my cool around cats and people is pretty easy. Probably the thing that I most need to practise patience with is Internet Explorer, as I occasionally feel annoyed and frustrated about it. (Not super-frustrated, but still pretty grumbly.) Maybe the next time I find myself peeved by cross-browser differences, I can remind myself of things to appreciate about IE. I'm sure the Internet would have grown slower without a default browser on lots of people's computers, and IE keeps lots of people employed or consulting–all the things that need to be tweaked. And things are getting better now! At least I don't have to code for IE6 any more, or even IE7. Besides, IE makes a good basis for humour. ;)

Philosophy. Not just for the big questions–also for the little tech annoyances opportunities to practise patience.