There's little doubt that good relationships make the world go round.
The bonds we share with our loved ones make us happier and more fulfilled. We can also expect to live longer, and enjoy more robust cognitive and mental health, as a result of strong interpersonal friendships.
Interestingly, this benefit applies to "weak ties" - the people we see on occasion or don't have deep contact with - as much as our lifelong pals, partners, family and close work colleagues.
The connections we have, large and small, affect the way we feel about life. They contribute to a sense of belonging - whether that's the man we see everyday on the checkout till or our BFF.
So, how do keep the wheels of these friendships oiled?
New York-based happiness guru Gretchen Rubin says it's all about adopting a specific rule - and then adopting it every time you see people.
Rubin, the best-selling author of multiple books on the art of happiness, says the point is not to make vague resolutions when it comes to relationships - such as "try to be kinder".
Appearing on a Facebook Live session with Business Insider, she says the key is to say a sincere and warm greeting every time someone you know arrives or leaves somewhere.
"It's to really recognize that someone is coming or going," says Rubin. "It's really to look the person in the eye; say hello; have a little exchange; and to acknowledge the fact that they are coming or going."
By saying hello or goodbye every time, you're utilising an easy, measurable tool that doesn't require much effort. But it can make a big difference in the way someone views their relationship with you.
"It's not like, 'Do three good deeds throughout the day,' when you're like, 'Oh, I totally forgot,'" Rubin says.
"I am amazed at how much it creates a sense of connection and recognition," she adds. "And that's what we want from our relationships."
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