Domestic blindness
1. "When my now ex-wife and I first started dating, I had made a roast for dinner in my slow cooker. After dinner, she was helping me clean up. I came into the kitchen, and she had the entire crockpot submerged in the sink. I asked what she was doing, and she said she was cleaning it. (She didn't know that the ceramic inside could be removed to clean). After I explained that to her, she said, 'I guess I shouldn't have put the whole thing under water!' I said, 'no!' and reached over and unplugged it! I have no idea how she didn't get electrocuted."
2. "I had an ex who didn't realise that vacuum cleaners had to be emptied. He genuinely thought the vacuum was broken because it was full of fluff and didn't suck any more. The worst thing was, I believed him that it was broken because it didn't occur to me that someone could think vacuum cleaners magically made dust disappear."
3. "[My partner] tried to make baked potatoes in the microwave for the first time. Wrapped them in tinfoil. Came to ask me why there were lightning bolts in the microwave and why it was getting very hot."
(Source: Reddit)