We've all encountered people in our lives who became our best friends for five minutes, only to be completely forgotten by the next day - mates you make in the loos at clubs, childhood holiday pals, those kind of people.
Unless you follow each other on Instagram or pop them a friend request on Facebook, it's often unlikely you'll ever meet again.
And then it was even harder back in the day, when you'd have to scribble down someone's landline number or their address, only to find they moved house a few months later.
However, apparently thanks to the power of the internet all is not lost. You just have to get yourself on Twitter and get social media to do the leg work for you, obviously.
Posting a photo of herself as a child with another girl, Twitter user Brianna wrote: "Hey twitter, I met this girl on a dinner cruise in Hawaii in 2006. We were basically best friends for that night so I need y'all to help me find my best friend cause I miss her and I need to see how she's doing now. Please retweet this so we can be reunited."
Leaving the tweet at '9 retweets' when she went to bed, Brianna soon found that the world totally had her back - and not only did her post rack up 174,000 likes, it also got retweeted 88,000 times.
Lo and behold, the message eventually reached her 'best friend' - who now tweets under the handle @heii_tree - who tweeted Brianna back with a photo of her as a kid wearing the exact same dress.
"OMG OMG HEY GIRL HEY GIRL HEY!!" Brianna replied, adding: "Omg my heart is so happy."
While many other Twitter users found the exchange 'so cute' and were left 'crying', some have used the opportunity to turn it into a bit of a meme - Photoshopping themselves into photos with girls they supposedly met in Hawaii in 2006.
Like Michelle Obama! Hey gurl!
Or Dua Lipa!
Another tweeted a photo of her own chlidhood bezzie, writing: "Hey twitter, I met this girl at Barbie Fairytopia Live in Kentucky in 2006. We were basically bestfriends for that night until she put broken glass in my sleeping bag and forced me to watch her eat her pet hermit crab. so I don't need y'all to find that crazy ass bitch, move on."
Another simply pointed out: "Unfortunately they'll soon realize they don't have much in common and will now only be social media friends. Hopefully I am wrong."
Harsh, but probably true.
Featured Image Credit: Twitter/@briannacry