That being said, I've seen two of them.
The first was that of my grandmother a few weeks after she had passed. She and my grandfather had moved back in with my dad when they became too old to take care of themselves. My grandmother passed peacefully, surrounded by family,in the bedroom down the hall from where I usually stayed when I visited. My grandfather stayed at the other end of the hall after she died. A few weeks later I was in town and stayed at my father's and when I had gotten up one night to go down the hall to the bathroom, I saw her coming out of the bathroom and she walked to the room where my grandfather was staying. I paused in the hallway but was not scared. She smiled when I saw her and she went into the room with my grandfather (without opening the door).
The next day I told my grandfather, "I don't want to sound..." he stopped me and said that he has seen her too a couple of times and that she is ok.
A couple of years later when my grandfather passed on (in the same room), we were at the graveside for his funeral. It was a cloudy, dreary day. After the preacher said a few words and turned the ceremony over to us, a wind came up and blew the clouds away. It was a clear blue sky and the wind stayed around for less than a minute before settling down and the clouds returned. "Well, Dad's gone home with Mom", my dad said. We all left knowing everything was groovy and were not too terribly sad. She had come to get him.