Today's gear grinder: People who refer to any hour on the clock as "xx bells" (ie 9:00pm, it's 9 bells), without any regard to what ship's bells actually mean. Bells were originally used during the 4 hour watch system, sounding at half hour intervals. There are never more than 8 bells.
The saying "8 bells, time to go home" is acceptable, as its origin stems from the fact that 8 bells signifies the end of one's watch.