Year 10 is the first year of Key Stage Four, and thus the GCSE syllabus. It's widely regarded as an excuse to mess about for a year, because most of the stuff learnt during this time is forgotten during the Summer Holidays between Years 10 and 11. Several students have taken this opportunity to practice lying and weaseling their way out of work set, before it becomes more necessary in the following year and Sixth Form.
It is important to note that teachers are not often changed in Years 10 and 11, in an attempt to minimise the difficulties a changeover inevitably brings. In other words, unless he or she leaves, you're stuck with any teacher you hate for two years.