If we met, you and I might bond over coffee and cake, or an after-work drink. We might find easy agreement over the All Blacks, or the Budget, or The Simpsons; we might discover a shared love for duck hunting, bread making or pole vaulting. We might say "let's do this again". Or not.
Pets are just the same - adjusting for obvious differences in diet, linguistic skills and political engagement. They bond and build friendships over shared interests. They value like-minded company.
It's just that, sometimes - usually - they express their bonding in a different way from us humans.
Rusty and Tabitha bond over a common interest in sleeping most of the time.
Possum the kitten and Missy Moo the dog have a close, smell-based friendship.
Ivy admires the way Echo's ears taste. Both of them admire the way the fire feels, close up.
Izzy and Molly know each other pretty well. Reader Debbie had to leave them in London with a friend after she had to shift to Sydney, and she still misses them.
Mali and Oscar got to chatting and discovered that they both love sleeping. Who knew?
When there are three of you, you can spoon and top-and-tail simultaneously. Here are Lily, Angel and McGee.
Ah, the back of the couch - a popular meeting place for Amber, Black Pearl and Bidi. (If cats had pubs, I'm sure there'd be a cosy one called The Back of the Couch. Also The Long Scratch, The Full Bowl and The Permanently Open Door.)
Company plus space - that's what a king bed offers. Reader Charissa sent this photo of her cats in a loose gathering.
Fiz, Sig and Pax all have somewhere soft to rest their chin.
West Highland Whites Jack and Nicky are inseparable.
Nothing unites cats like somewhere to perch and something to stare at. Here are Spaz and Giles - please use your imagination to see their tails swishing in unison.
These two seem to have formed a similar opinion about whatever it is they're looking at.
Max and Kharn share an excited moment. Owner Kirsten tells their story: "Both were adopted from Dogwatch Sanctuary Trust but 18 months apart. They are best friends and got on great from the start. Their favourite run is the one at night when they get to run around the park and hunt for rabbits and possums. Max seems to have a special skill for hunting out hedgehogs. Kharn's special skill is not coming back when called and sneaking on to the bed at 5 every morning and eventually pushing you out."
Digby and Aloysius love nature.
Bailey and Cully are sisters - so don't you try to separate them.
Billie and Arlo have each other's back.
Tilly and Isla are outdoors girls.
Gus and Bonnie are ready for the next adventure, especially if it involves a chase.
Jake, Ella and Jay practise their respective adorable faces.
George, Molly, Poppy and Jet want something exciting to happen. It might not, but that won't stop them from being optimistic.
"She's a hot one today." says Ben. "Oath," says Chance.
Molly the Foxy has the sun. Riley the Ragdoll has the sun and the shade.
Otis and Salem have a bond that keeps growing.
Meet Teke Tali and Cupcake, a couple of happy goats.
Who, us? Derringer and Winchester don't know what you're talking about.
Shei and Maisie are big girls whose lovable presence you could never miss. But don't lose sight of their foster kitty, Little Man. Literally, don't lose sight of him, among the magazines.
Great friendships occasionally have their tense moments. Rufus and Betty, normally the best of mates, seem to be in a tetchy mood with each other.
Jovi and Jett are buddies now, but it wasn't always so. Back then, Jovi used to give Jett a telling-off for daring to share the bed.
Finally, when friendship and rivalry melt into a single phenomenon understandable only to the four-legged: Kobi and Steel Balls have a playfight. Or is it play. Or is it fight.
Thanks to all for posting your photos. Please email me your own photos, or go to the Four Legs Good Facebook page and use the Upload Photo button. While you're there, browse through the thousands of photos that readers have posted by clicking the Photos link.