Other than the health and religion questions, do you not think the government in some capacity knows all of the things it is asking already? If you have ever claimed a benefit of any sort, or paid council tax, then much of this information is already at their disposal.
Its an inconvenience, but there is really very little on there that they dont already know. Its just a way of taking a snapshot of society that will provide an insight into the public of 2011 and provide a record for future generations. Dont think too much about it.