I have been to rather too many, even though I'm normally a highly logical person who really shouldn't be giving this sort of thing any credence whatsoever: after all, the vast majority of mainstream psychics in the media have been exposed as cold (or hot) readers at some point or another. I think it's the one thing I'm gullible about. Maybe it's because I have a lot of close relatives who are no longer around.
My weirdest experience was when I moved house and looked for one in the Yellow Pages, and the only one I could find was called something like '(First Name) International Clairvoyant', and I immediately thought 'I'm not wasting money on anyone who doesn't advertise under their real name - they're probably fake'.
Then I got an odd, strong feeling that I should open the other phone book in the house and turn to a specific page number, and I did - and the first number I saw was this psychic's phone number, under her real name.
It was a RIDICULOUS coincidence. She told me she'd stopped taking readings but she would make an exception in this case; after the coincidence I'd had, I think I was expecting some kind of Damascene experience, but the reading turned out to be a mild disappointment.
I'd say: 1/3 were on to something and not necessarily cold reading, 1/3 were clear frauds and 1/3 had issues that merited a visit to a doctor.