Things to do at work, when you must get away:
1) Take a walk. 15 minutes outside is a godsend.
2) Listen to a 10-minute meditation podcast. There are a lot of podcasts on iTunes. College Behavioral Health Centers are a great (free) resource.
3) Combine #s 1 & 2.
4) My personal favorite: Listen to a quiet mix (with a sleep or relax theme), with ambient sounds in the background. I use my iTunes playlists with water, rain, submerged ocean sounds, etc., on the Ambience app. I use the paid version, which is about $3.00.
5) Try a creative writing technique, like writing yourself a letter to get out the frustration before taking it out on a co-worker. I email myself, home-account to home-account.