At work today, I set out to fix a bug on my bug list. While I was working on it, I found a small bug that was preventing me from testing the fix, so I fixed that. I also found two other annoying bugs that I wrote up as new bugs for the appropriate people to fix.
Net bug score: one bug removed from the list, one other bug fixed without ever hitting the list, two bugs added to the list. bugCount = +1, although xBugCount (which is a more accurate version of the statistic) is 0.