IT'S the small interactions in life that can make the biggest of differences.
Bundaberg mother Christie Kelly is testament to this as she shares the moment a stranger's actions changed her world.
It was a breakthrough that may seem small to some, but meant the world to her.
Mrs Kelly's three-year-old son Theodore has never spoken to strangers and will not normally look at people.
He is selectively mute and will only speak when comfortable, rarely speaking to his mum or dad.
Mrs Kelly was almost knocked over as she did her weekly shopping at Coles and heard her child speak in public for the first time.
The cashier, Tiffany, began asking little Theodore if he liked Tiny Teddies when he replied "yes” and then continued to answer "yes” and "no” to many more questions.
The mother-of-four said it was a huge breakthrough for her son who was also diagnosed with autism two weeks ago.
"I was stunned,” she said.
"He has limited speech, but really opened up for the first time.
"I thought 'I could stay here all day and listen to this'.”
Selective mutism is a condition where children are able to talk comfortably in some situations such as home or around familiar relatives, but are not able to use their voice in other social situations where there is an expectation for speaking such as at school or with less familiar people.
It is a form of social anxiety where the child fears when people hear their voice they will react in a way that might be embarrassing for them.
It is usually diagnosed at three years of age.
Mrs Kelly took to social media to thank the young woman who took the time to bring her son out of the quiet.
She said it was difficult to have a child who was selectively mute some days, especially in social environments.
The post on the Coles Facebook page has now gone viral with almost 2000 likes, 66 comments and 70 shares.
With comments from people saying they had or know children with selective mustism and it was amazing to hear Theodore connected with someone.
"That's so amazing, made me cry,” Facebooker Donna Paton said.
And Mandy Alaban said as an ASD mother she knew the great feeling Mrs Kelly would have had watching her "little superman” engage how he did.
Coles replied to the post saying it was fantastic to hear and that Tiffany at the Kensington store made such great efforts to engage with the little one.
Others said maybe the young woman should look at a new career in childcare, but Mrs Kelly said Tiffany was a great advocate for Coles and she would definitely shop there from now on.
"Tiffany did such a wonderful job and she just needs to keep doing what she is doing,” she said.