The Moon is who we are at our most instinctive. This is our "flow", the way we naturally operate without much thought or deliberation. When we're stuck in situations in the world that oppose the nature of our Moon sign, our flow is blocked and we become unhappy and unfulfilled. That energy then becomes destructive or negative. So, look to your Moon sign as the best way to tap into your own flow and operate most happily. It also represents what makes you most comfortable and what can subsequently provoke feelings of unease or insecurity within you.
Our intimate relationships are heavily influenced by our Moon, as this sign symbolizes the manner in which we emotionally connect with others. It's also how we take care of others. This is going to manifest differently for all of the signs. Some will be more sympathetic, others more practical. Some people's Moon signs will allow them to be very emotionally effusive, while other's Moons can cause them to be more restrained when being intimate.
Although it's said (and is true) that women express their Moon sign strongly when they become mothers, I believe that men also express their Moon sign quite prominently when they become fathers (even though their nurturing style is often a bit different). The Moon sign is the kind of parent that we'll end up becoming, male or female, as the caregiving methods of our Moon placement instantly kick in once we have another life to take care of. We embody the energy of our Moon sign in our parenting style in a way that's quite instinctive. No one teaches you how to be a parent, after all. You just learn as you go. So look to the Moon sign to see the natural parenting skills you possess, as well as trouble areas you might need to work on or watch out for.