The contestants are asked to strive for the sort of perfection displayed by Janet Jackson on Saturday 's show , in which every jerk and twizzle of her and her 8,000 dancers was choreographed with tedious mathematical precision as she span about in one of those microphones that make performers look like they 're working in a call centre , and seeing as she was presumably miming she must have been wearing it so she could do a bit of extra work for British Telecom while she was on .