Touch something metal before working on a box.
I have never used one and I have worked on my own boxes for around 10 years. I have never had a problem.
I actually got electrocuted when re-installing a sound card on the MSI KT3 Ultra I'm using now, and it still works fine.
That is why I'm a pretty hardcore MSI fan. Anyways, yea I'm talking really electrocuted. Enough to blow my arm out of the box and knock me over.
Like the person up there said. They're overrated.
Just touch a ground before going in.