I'm happy to throw my cards on the table and to state without doubt that I believe in ghosts. I've seen and heard a number of them in my lifetime. Some were people close to me, others had no association to me personally, though I'm certain had an attachment to the building where I had the experience and some have been animals (I've written about the ghost cat I lived with elsewhere on these forums). One I can offer no explanation for.
Without boring you, a very brief summation of some of the encounters I've had.
Age 14, 1979. My family move to a large rambling 49 room house in the country. Old by Australian standards. The house was in a ''U'' shape with one wing two stories and the former staff quarters. Exploring rooms full of leftover items from the previous owners, I use the upstairs bathroom one afternoon. I wash my hands and exit the room only to see on the landing a figure in what appears to be a military uniform staring out the window. I could see right through him. He was outlined in a fuzzy, purple haze which appeared to be as though it was electrified. I was no more than 20 feet from the figure and watched it for 30 seconds or so until it simply faded before my eyes. My only exit was down the stair via the landing where it had been standing. It terrified me. My mother also saw a ghostly woman walk out of one bedroom, down a hallway and into another bedroom one night. There is a gatehouse on the property where I believe something evil resides. That's a whole other story.
Forward to 1987. My father had passed away from a cerebral hemorrhage in November of 1985. No signs of illness beforehand. He woke up, went to work, collapsed and died the following afternoon. My sister and I donated both of his kidneys. My fiancee at the time and I had moved into a new apartment. We both smoked at the time. I woke one night with the feeling that something was not right. I went downstairs only to see a faint glowing, golden light. My father was standing there. I had the overwhelming sense, that although he didn't speak, that he was trying to say that he (and everything) would be alright.
1989 to 1997 The house with the ghost cat that I have written about previously. He was big and black and regularly sighted. He was quite a friendly creature I sensed and he never bother me or my family.
2011 to Present. My wife and I own two gift stores. One is definitely haunted. It previously was the town bakery and the baker was an Austrian fellow who had a reputation as quite a drunkard. He didn't die on the premises, but when the store is closed, you can hear footsteps walking on the floorboards and he loves to mess the greeting cards up especially after we've just finished tidying them up. He's not sinister at all, just playful. You sometimes see the occasional shadow moving about, though rarely.
Our home, 2008 to present. My first wife and I separated in 1990. She passed away in 2009 after taking her own life. Around a month after the death, I was at home working along (doing graphic design/web design work) when I distinctly heard her voice say both my name and ''Goodbye''. The only other living being in the house at the time were our two small dogs, who certainly cannot speak. I found this to be quite disconcerting and eerie. I assumed she was coming to see me one last time, though I couldn't understand why as we were not on good terms.
My present wife (together 18 years) and I also had two ghosts in our home, one a little girl who we'd often hear weeping or talking to herself and and older lady who we'd sometimes see moving from door to door across the hallway. A psychic friend of ours told us that the older woman was scaring one of our dogs, hence why he was wetting inside all the time, so after reading some up on some banishing rituals, I gave it a try and moved them along. It seemed to have worked as we have not heard nor seen neither since, and our dog is much better behaved.
Our female dog Poppy passed away in October just gone, yet twice in the past two weeks, I've been convinced I've seen our other dog Toby running down the stairs or hallway, only to find he's been with my wife on both occasions (he's a mummy's boy). I'm hoping it's her, still enjoying her home here with us. The glimpses have been fleeting, but they make me happy.
Make of all of the above what you will. I can't tell you what ''ghosts'' are, I can only tell you of what I've personally seen and heard.