When are lower rates of unemployment a bad thing?...When the rate drops because more working-age adults simply stop looking for work, essentially giving up on finding a job.
For instance, the most recent Labor Department report showed the economy added 96,000 jobs in August, down from a revised gain of 141,000 in July. While the unemployment rate fell to 8.1 percent from 8.3 percent in July, that resulted from more people giving up looking for work.
BTW, before you give up looking for work, why not check out the Job Search page at Stuff Economics. It may prove helpful.