What da reason for this?

[TheMisdirectingHand]

Those mistakes are usually because your friend is running out of material, or it is because his mind is blank at the moment. Why would be he performing magic to the same person for half an hour? If you don't want people to think he is the only magician, look for other people. He may just be performing consistently because he think it will keep up his reputation as a magician.

Also, I don't think I am a natural either. There is one other person at my school who knows very basic sleight of hand... but he tries to overdo everything, I taught him one or two effects myself. It is not whether we are a natural at magic or not, it is how we start ourselves it in the first place. If one has a calm and cool-headed personality, there is a chance he would be a great magician, comedian, lawyer, etc.

Practice is one of those "time-killers." It is great because we do not know that we have gotten better at something until we perform again. When I have too much time on my hands, I whip out my cards. One time I was practicing my lifts and pass for an hour without being fully aware of the time. That paid off a great amount in live performances.