Whether it's the last word from a partner you can't get over, or precious words from a loved one who has passed away, many of us have messages on our phones we just can't bear to get rid of.
And thousands of people have shared the words they will never be able to forget with the world on the Tumblr account, The Last Message Received Tumblr, founded by 16-year-old Emily Trunko from Ohio.
From those left wondering why they didn't see the signs before a loved one took their own life, to those left wondering why a cherished friendship wrong, some of the most recent submissions are truly heartbreaking.
One added in the last 24 hours comes from a woman mourning her fiancé.
"He sent me the link to John Legend's All Of Me and told me to add it to our wedding playlist," she explained.
"He committed suicide at work the following night. I still regret not seeing any of the signs."
Another woman kept her ex-boyfriend's message, no doubt as a reminder to herself never to be treated in the same way again.
He'd written to her: "How did you not see the signs?! You dumb b****."
She explained: "Last words of my ex boyfriend who was sleeping with his best friend's sister during our eight month relationship."
Another woman revealed a more amicable break up with her ex as she shared their final exchange over text.
Neither could figure out where it had gone wrong, but she told her ex: "Thank you for talking to me. I just kinda wanted to make things on better terms, and yeah I'm really sorry again for the way I handled things."
He replied: "Of course and sorry for everything I did as well."
Sharing their exchange, the woman revealed that she was not over the relationship.
"I still love him so much," she added
Another tear-jerking exchange took place between a woman and her boyfriend's younger brother who she reached out to after noticing he was struggling.
He told her not to worry, saying he was just "an edgy teen" and said he didn't want to talk about anything.
"He shot himself shortly after this. He was 13. I miss you, O. He was family," she explained.
A heartbroken woman shared the text she sent to a friend she'd become romantically involved with only to discover he was still seeing his girlfriend.
"Thank you for proving me right about why I should never do that," she said. "Never let people in."
He simply replied: "I'm sorry."
"I honestly thought this was our chance to finally be together," she explained in her post.
"All he could say was sorry. It's been a long four days without him and I don't know how I'm going to survive."
Another simple "I'm sorry" was the last message a lovelorn young man received from his girlfriend after she went off to college.
"A week before she was telling me how her first thought in the morning was of sleepy morning kisses with me, then every night she thought of coming home to me," he said.
"The next she was dropping me cold out of her life. it's still hurts to see how easy it was for her, someone i really loved, to do that, but im slowly getting better. I still miss talking to her about the little things."
A final war of words between lovers ended on a poignant note as the man admitted he misses the person who he used to be.
After telling his former partner to be with someone who can make her happy, Seth claims that she 'destroyed' the person he once was.
She lays the blame back with him, before saying: "Goodbye. Just so you know, I miss Seth. Old and new."
He replied: "I miss him too."
One man was left wondering after what might have been after an ex contacted him right before her wedding to ask if the could ever be together again.
"We are both married now. Her to him and me to another girl," he explained. "I sometimes wonder what my life might be like if I said yes."
A woman explained that she was still struggling after an old lover failed to show up to see her.
She'd told him: "Only make plans you will follow through with."
He replied: "I will".
But she felt like "a fool" because he didn't stick to his word.
"And still a fool because I'm still waiting for him to show up," she said. "I miss you."
A devastated woman also revealed the final text from a friend she was in love with.
He asked her to spend time with him because he wanted cheering up and they agreed to meet later.
"Oh god, I miss him. He got into a car crash that night and died instantly," she said.
"I don't think I'll ever get over this awful, awful pain. I don't know if I'll ever breathe or think normally again. I don't know how to survive anymore. I need help."
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• Samaritans 0800 726 666
• If it is an emergency and you feel like you or someone else is at risk, call 111.