Is bradycardia (low heart rate) bad, if you never feel faint or any other problem?

Depends. Some bradycardia can due to medicines called beta blockers, or a natural effect of good conditioning as seen in athletes. However, it can be a sign of serious heart disease impairing the electrical system of the heart. See your health care provider to evaluate the causes.
Low Heart Rate. People who are atheletic tend to have lower heart rate at baseline. If you do not have any symptoms such as dizziness or feeling light headed or you do not experience palpitation then it should be ok. Some individuals who are very atheletic can have a heart rate as low as 40s when calm or sleeping and they are usually asymptomatic. However, if you experience any symptoms then you need to see a dr.