The thing with all these shows is that they have some sort of 'proof' each week. The main presenters understanding of the word 'proof' is different from the rest of the worlds understanding of the word.
Also each different ghost show and there have been many over the years have different types of 'proof'
For example, loosening a torch cap and battery so it gets momentary contact and flashes on and off randomly is 'proof' that a ghost is communicating with someone. But if you look on youtube a man did it with out the whole ghost thing to prove it just happens anyway.
On a UK show they had a man who would become 'possessed' by a spirit on most shows and would then carry on to talk nonsense for a few minutes before passing out.
On another show they had 'images' of shadow people walking about.
On another show they had EVP 'proving' a ghost was talking to them.
On another show they had a 'Ghostbox' that randomly tunes through radio stations rapidly so picks up the odd word, and that it apparently proof of a ghost talking?
And so on and so forth. If you sit and look at the actual evidence they have then it is just not convincing. Also they dress it up and present in such a way that you might get a bit spooked before seeing something and you might just believe it, but in the cold hard light of day it looks fake or like something easily explainable.
I still enjoy watching the odd show now and again just for what people can convince themselves to believe.