No, and no.
I mean, I've looked for ghosts, even in places that were reputed to be haunted. I even prefer spending time at moody places where the sensitive would spot ghosts all over. I haven't seen anything.
I have had several friends who've claimed to know ghosts, usually on a scale where they've had "pet" supernatural creatures. Similar with UFO's. But in both cases, I have reasons to doubt these people's objectivity. (And in a similar case, I've known people who claimed that friends of theirs into magic or with psychic abilities or whatever would often have very tangible displays, to which I say bull; if there were people like that, wouldn't at least one of them decide to make a grand showing for power, fame, money, or just to stroke their ego?)
I guess my biggest thing is that I need proof. And for all the reported cases, there has yet to be one alien, psychic, ghost, or whatnot that has fouled up and given themselves away, despite the rate of claimed encounters. Plus the fact that people often see what they expect. (Correct me if I'm wrong, but I remember hearing re: recovered memories that if both the patient and the therapist were into alien abductions, there'd be rock-solid memories of abductions, while if both thought ritual abuse was to blame, everyone involved would be absolutely convinced it was a satanic cult. Why did so many "abductees" in pre-industrial cultures see their local saints/imps/whatnot, while we see little grey men instead of elves? It all smacks me as too subjective to be true.)