If ghosts are a product of the "Stone Tape" theory, then presumably they are not aware of us, anymore than Adele is aware of us yapping whilst recordings of her songs are playing.
If it's some form of time-travel then interaction could be feasible and possibly distressing for everyone involved. However, for all the people involved to become distressed would involve the 21st century accidental traveller (travelling backwards) desisting in looking at its smartphone for more than a second and actually observing the world around them, so maybe only distressing for the people who inadvertently travel from the past/encounter the traveller from the future...obviously I'm only thinking about travel between the present day and the past.
If I died tonight and woke up tomorrow with awareness that I was now a ghost I would be terrified. Truly, truly scared. Assuming that the ghost world doesn't provide support networks, it would take one heck of a lot of getting used to. Then, if you still have freedom of choice in the spirit world, it might become quite fun. But probably only if, like me, you relish being alone.
If I woke up unaware that I was a ghost I think I'd be baffled for a very long time.
I'm guessing that if you woke up as an otter or daffodil you probably won't know that you've just woken up as an otter or daffodil, as opposed to the human that you were before, and you'd simply accept the situation and get on with your otter/daffodil life. When I was born as a human baby, I had no distress or awareness that I was no longer a polar bear. I just got on with being a baby. A very chubby baby! (So far as I'm aware, I wasn't a polar bear in a previous life, but that's only based on my awareness. Who knows what, if anything, I was before...)