It comes across as either nerves or inexperience (or lack of rehearsal with these particular effects). I know J.B. certainly has plenty of experience, so maybe the latter. It could also be that these handlings play perfectly fine in the real world, but not so much for the unblinking eye, as Richard pointed out. The dynamic is entirely different, unless shot in such a way as to mimic the real-world experience in a first person fashion as closely as possible. A good example is the goldfish production for the kids. No doubt they were amazed, but the whole thing viewed in a wide shot like that makes it all look a bit 'fishy', and any layperson will spot some dirty work on a 2nd viewing, if it doesn't leap out in the first. Composing the shot differently would have helped, but even better, in my opinion would have been JB being comfortable with the certain something. He seemed, even at the end to be very conscious of it and working too hard to conceal.
Also, I noticed he was doing a few of the effects David Blaine did on his first and second specials. Not sure why you'd want to do exactly the same stuff, especially in the same format of show (i.e., "street" magic). The show even has the same title as Blaines's 2nd tv special, not that the laypeeps recall.