I think that looking someone in the eye is an important thing for upholding happy relationships, be they romantic or friendship.
At the beginning of a romantic relationship you spend ages gazing into each others eyes, ignoring the rest of the world. But as time goes by, more and more of the conversation is done looking into the distance, at random things on the table or just at the other person’s ear or jaw line or hair or your own hands. The more we do this, the less the other person feels like a person, and it gets easier and easier to place them in the category of ‘those things that don’t feel like I do’. We start assuming they don’t care, that they don’t have as complex emotions as we do, that they’re all straightforward robotics.
Have you ever been stood opposite someone you have only known for a couple of minutes or an hour, and looked them in the eye for a whole 60 seconds? I have. And you should, if you even get the chance (I don’t recommend walking up to strangers in the street and asking them to look at you for a minute…) What happens is, that the process of getting to know someone accelerates – that person, who 60 seconds ago was only a human figure with a name, a language, a hair colour, and perhaps a personality you could describe in three words, sometimes called that ‘first impression’. This is usually confined to generic things like ‘shy’, ‘brash’, ‘charismatic’ etc. After those 60 seconds you are facing, not a two-dimensional remote figure, but a complex human being with a past and a future, with individual reactions to everything going on around them, with hopes and dreams, fears and worries, with an eagerness or a hesitation to explore the world. And all this without having exchanged a single word with them.
Imagine then what the effect is on a relationship, if the eye contact is lost? Arguments start to drag along the lines of ‘well you clearly don’t understand where I’m coming from, you’re just doing this because (insert reason)’. If, instead, you uphold the eye contact regularly, when saying ‘I love you’ most importantly, but also just when asking if your partner wants something from the kitchen, if the want to watch this particular film, or when telling them something about your day. Look them in the eye, and actually communicate with the person you are having a relationship with. They ate just as complex as you, and the eyes are the one place where they are unlikely to be able to hide that from you.