Ren's Footprints

Last week I finally bought something to keep in my bathroom to give it a better aroma. I found some incense that smelled good, bought them, and started using them right away.
Soon after that Miho came over for a visit and noticed the smell, but never mentioned anything to me. However, the next time she came over she saw the incense burning and asked, "Where did you get these?"
I explained that I had just bought them because I liked the smell. Then she said "They are for dead people!"
She then explained in more detail how these are the incense that you burn on your in-house memorial of a dead loved one. Such memorials are really common here. People also use such incense at graves.
She said the last time she visited she thought for some reason the place smelled like her grandma's house but she didn't mention it.
This has been the biggest cross-cultural blunder of my stay so far. A male, American classmate of mine once rode the "ladies only" car of the subway for a long duration without realizing his mistake. Tokyo subways are so crowded in the mornings that they have "ladies only" to prevent groping.