Sarah Cowan, from Dumfries, was persuaded by her husband Darren to pick up the groceries on her way back from a long shift at work.
"I was absolutely exhausted and just wanted to go home," the 48-year-old hotel worker recalled.
"I did the food shop as quick as I could and thought I'd milk it so told Darren he had to run me a nice, hot bath to come home to."
However, the mum-of-one's bath was short-lived when Darren was unable to locate the £75 ($100) food shop.
Sarah said: "He was shouting up the stairs and asking where the shopping was - I thought, 'What is he doing?'
"I told him there were two big blue Ikea laundry bags in the boot alongside my dusty pink handbag but he insisted the boot was empty.
"I was annoyed enough before having to go downstairs, but then I saw the empty boot and slowly realised I must have unlocked the wrong car and put my shopping in the wrong boot."
Yep, it appears a combination of fatigue and misfortune led Sarah to load all of her shopping into the wrong car.
She believes she must have been parked next to another silver Nissan Qashqai, putting her grub into the stranger's car, before returning her trolley and driving home in her car.
She said: "My car is a new one and you don't need to press anything on your keys to open the car, it just unlocks as you walk towards it with the keys still in your pocket.
"I opened the boot and saw that it looked slightly different to normal. It was like the bottom where the spare wheel usually is had been moved, so I wondered why Darren had done that.
"I was tired so I just put the shopping in, returned the trolley and went straight home."
Thankfully, Aldi confirmed the stranger had returned all of the shopping to the store - as well as Sarah's handbag, which is worth £250 ($339) and is of great sentimental value.
Sarah said: "I honestly thought I'd lost everything.
"I rang customer services and explained the weird situation, but couldn't believe it when they said someone had handed the lot in.
"It was such a lovely surprise, I couldn't believe that someone had handed them in. It just goes to show that there are some good people still out there.
"With the state of how the whole world is at the moment, its been so lovely to see such a kind gesture.
"I'm so grateful to get not only the shopping back, but my handbag too - it was the last present from my late grandfather so had great sentimental value too."