Marie Byrne took to the UK retailer's Facebook page to complain about an incident involving her elderly parents that took place in the store's Blanchardstown branch.
She explains that her parents were in the coffee shop for a pot of tea and on finding it a little weak for their taste and asking for a second teabag, they were told they'd have to pay for it.
And people are mad.
Like really mad.
Marie's Facebook post has over 9,000 likes and 790 comments - most agreeing that the policy is an utter disgrace.
Some even pointed out that this is even more of an affront as it's a known fact that older people like their tea strong. And a good few were so offended they vowed to never shop at Marks again.
Of course there were also those urging for calm, pointing out that this wasn't the end of the world.
Marks and Spencer's have since offered two attempts to placate the masses but it seems that the damage is done.
They have also asked Marie Byrne to send on her contact details so the store can contact her directly.
The incident has been covered in various UK media outlets - with most of them taking it as a lesson tomess with an Irish person's tea.