Ghosts as dead humans wandering in the afterlife and interacting - No
I've seen a lot of interesting stuff over the years though and I wouldn't be surprised if we find there is some type of energy manifestation that can get left behind like an imprint. Similar to how records are just sound vibrations cut into vinyl, there may be a way for life-energy to make a similar imprint.
When we see ghosts, it may simply be an imprint playing back like a record or video tape. Most sightings are benign and it's just seeing a ghost walking down a hall or standing around. For the people that have studied ghosts seriously, there is an increased magnetic response when ghosts are seen and this may be the key to getting to watch "ghosts".
Just like you need a needle to go into a groove to listen to a vinyl record, maybe one day (if that's what it is), we can have some kind of electric field generator device to watch ghosts.