Yes. But, I've never had any encounters with one. I have, however, had some unexplained things happen.
On two occasions, both late at night, I've smelled perfume. I live with my dad and grandparents and none of us even wears any perfume, period, let alone late at night.
At my old job when I used to work, I saw the shadowy form of a man wearing a wide brim hat, like one a cowboy would wear. This was at night, too, when I was working late. I went outside as fast as I could to see if I could see who the man was. But, he was gone. I never saw him before or since. To this day, I still don't know who he was.
I've seen orbs in the attic when I used to go up there with my video camera. On a few occasions, the camera light went out. But, once, the battery drained. I remember there was roughly 80 minutes of battery power before it drained in the attic. I left the attic, went into another room, and turned my camera back on. There was STILL roughly 80 minutes of battery power.
I've had other experiences, but those seem to be the ones that stood out the most for me. Was I experiencing ghostly phenomenon...or could there be logical explanations for those experiences? And, if so...what?