I have seen and experienced what
@Colonel Valerio is saying first hand as my wife and I used to be Pastors in Charismatics circles. People claim to be healed and then two months later they are no better off then they were before. There is quite a bit of manipulation in the process also. Today I will even admit that I was likely guilty of engaging in those techniques to a small degree without even realizing it.
Just recently my wife and I went to check out a new church we heard about and thought maybe it was something we could tolerate (we have been in a wilderness finding a somehwere to fellowship for some time). However the third meeting we went to, the minister had an altar call and began praying and "prophecying" over people. He called my wife and I out and asked if he could pray for us. I have confidence in my discernment so I allowed him to. The whole time he was praying for me I keep my eyes open and was starring him right in the eye and asking God to help me discern if this guy was legitimate. I got the distinct feeling it freaked him out. It's like he knew he couldn't play some mind game with me or pull the wool over my eye. He ended up not really speaking much of anything to us (which was just fine with me), as if he didn't really hear anything from the Spirit of God, unlike the 3 or 4 people he prayed for before us. He confidently spoke very specific things over those people as though he had heard something directly from God. It's almost as if he knew he could hoodwink those people into believing he was actually hearing from God, but he new he couldn't play the same trick on us.
Shortly after that he prayed for another lady who said she had back issues. After he prayed for her he asked her if there was something she was able to do because of her back. She replied by saying she couldn't pick and hold her 5 year old daughter. So the minister tells the 5 year old daughter to come up and had the poor lady pick her up. If was obvious she was still in pain, but she did it anyways. The guy starts "praising" God like it was some miracle while the poor lady is practically in tears from the pain. Because I was standing right next to her, I could see she was trying to put her daughter down, but the minister put his hand in the way and kinda of helped hold the child up and kept the lady from putting the child down.
The whole sequence just really pissed me off. Needless to say we have not gone back.
Through my almost 30 years of running in Charismatic circles, I have seen plenty of this to varying degrees, yet I know I have seen genuine miracles and prophecies from God (and I believe that God has ministered to others in that manner through my wife and I). But I have to admit that 75% or more of what I have witnessed is more manipulation and pyschological mind games. I'm not even saying that all the "ministers" who engage in these practices are purposely trying to manipulate or fool people. Most of them have been fooled into thinking what they are doing is genuine, because they are only copying others who they think are the real deal.