When you reflect on the most memorable events, experiences, and moments in your life, you'll notice that they have something in common: the presence of another person.
The best moments - and most agonising - occur at the intersection between two people. Yet we often underestimate the impact of our closest relationships and social connections.
Scientists are discovering how relationships shape our expectations, desires and goals. Emotions spread quickly from one person to the next. When you see a friend who is happy, this often causes you to smile, and as a result, you feel better. Or if you have a frustrating meeting late in the day, your emotional state is likely to transfer to your spouse when you get home. Because we tend to synchronize our moods with the people around us, our emotions influence one another throughout the day.