squirrel crossing a quiet country road....instead of a tiny boat on a HUGE empty ocean. You never know when the next Prius (no engine sounds) will come over the hill and leave you too scared to made a decission on which way to run.
It's been my experience that daylight encounters with ships are more surprising than those at night where the ships' running lights more easily define its direction and any changes in course. The 'closing' time of when a ship appears over the horizon and is ready to take you down can be as little as 10 minutes but not much longer than 15.
How long does it take you to go below and check a chart position or heat some soup for the midwatch?