The scientific studies on this topic prove how viral our mood is. Everyday we choose our mood. Our outlook on life directly affects those closest to us. Have you ever met someone who is continually discontent? This individual may not be your first choice for friendship.
We must not let our circumstances control our mood. It's our choice. Have you ever noticed if you are grouchy, your spouse may also start acting grouchy, and the kids all of a sudden start whining as well?
It is a domino effect.
In my opinion, we either make those around us better or worse - staying the same is rarely reality.
To broaden the topic, this is not only true with our mood; it is also related to our work ethic, how we love, our sincerity, and the list goes on.
In the end, I would rather be optimistic and wrong, than pessimistic and right, especially when I consider how my outlook impacts those I love the most.