I've a friend who loves baking and her DH of 40 odd years had bought her an electric food mixer for her birthday, the kind on a stand with its own bowl, which she always left on her kitchen counter, ready for use. He died within a year and around the time of their anniversary the first year she was alone, a family member came to stay overnight with her because M was so sad. Her and the friend were both woken, sound asleep in different rooms, by the sound of the electric mixer whirring away at 5 a.m. on the anniversary day.
Here's another one - husband and I stopped at a country hotel on a dark and misty night, taking a chance, broke our journey due to bad weather. We're told the hotel is full, but then the receptionist and other staff member have a little conflab and eventually we're told 'okay, there is a room'. Fast asleep in the early hours of the morning, I'm awoken by what felt like something/someone walking across the bottom of the bed. Sat bolt upright, husband - who is scared of nothing and no one, leaps up, says "What was that?" He had experienced it too. We put the light on, checked the room, windows were shut tight, door locked. Nothing there. We struggled to settle down back to sleep, bit unnerved. Next morning, told the staff, who exchanged knowing looks ... we were out of there as fast as can be!