Hi Amanda and everybody, good topic!
I think BetterMost can be a stress reliever. I myself use it as an escape when RL gets too stressful. It immediately takes me to another world, in a way, so by the time I return to RL I feel better. Sometimes getting away for a while really is helpful.
I've also had a lot of luck with walks. Maybe for similar reasons. When I feel depressed or stressed, and I take a walk I almost always feel much better by the time I'm done.
As Janice says, breathing can be helpful for quick relief. The breath counts I've seen recommended before are slightly different (Dr. Andrew Weil has one that's something like 4 counts in through nose, hold for four, out for seven -- or something like that, anyway), but that probably isn't a big deal. The main point is to stop, breathe, concentrate on your breathing. Part of the benefit is just pausing to relax, but breathing itself seems to have some kind of magical quality. The explanation I've heard is that it's the doorway between our conscious actions (things we do deliberately, like walking or typing) and our unconscious actions (things we do on autopilot, like digesting or our heart beating) -- breathing can be either one.