Learned a lesson on flat calm at a mooring ball when the boat does the dance. make sure your bridle to the ball is tight. A longer bridle can wrap the chain from the ball to the anchor block around your keel. Waking up to have to deal with a chain wrapped around your keel is not a great way to start the day.

I make sure the pennant is up tight to the bow, with two lines.

This applies more to mono-hulls, but I saw one "special" that managed to have so much line out on a cat, that he wrapped the rudder.