It has been my experience that 'good' psychics are simply better at cold reading people than 'bad' ones. Most people do not understand the mechanics of how the mind works well enough to be able to make a educated choice about such so called abilities.
People, as a rule, think they know enough to know when they are being conned. And most of the time they are oh so wrong! The reality is quite the opposite. Most people haven't a clue how to tell the one from the other.
A great test was done fairly recently. Groups of six people at a time off the street volunteered to have a psychic tell them all about themselves, and what they desired for the future. The psychic talked to all of them as a group and again each individually. He then went to another room and spent several hours writing up a synopsis for each individual.
When he came back out, he asked them to take their reports and every one of them were astounded at how much this man knew about who they were, what their desires were, and so on. All six said the psychic nailed it.
The psychic then asked them to each trade off their report with another person in the group, so that every one had someone else's report. He asked them to read them to see what they thought.
The six found out that it was the exact same synopsis for all of them. All six reports were exactly the same. With each new group the event went precisely the same way. Incredulous belief in the psychic at first, sheepish acknowledgement at how easily they were fooled afterwards.
The moral of the story is not that people are stupid. Or that they are too gullible, or any of that. The moral is that it is very easy for someone trained in how the human mind functions to mislead someone who has no such training. The large majority of us are in the latter group.