The Ghost in the Hall
We used to live in a new, largish home for a couple of years. I had small children - 12, 8, and 18 months - so was attuned to children up at night.
I heard someone walk up the hall a couple of times, and went to look. I saw a figure enter the bathroom, so called out as I followed them in and turned on the light: no one there. I wasn't frightened, but thought "So, this is how it happens!"
I told my wife, who thought I was making it up and scolded me for scaring her, and admonished me NOT to tell the children, which I didn't.
Months went by, and I had heard the steps and seen the figure a couple of other times. One day, I overheard my wife telling someone that she had seen the ghost I described, but didn't want to admit it to me.
Then one of our children talked about it!
Although the steps faded, returning occasionally, the ghost never caused any trouble, but was an interesting revelation to all of us doubters.