Earlier quoted context omitted.
VAT is crazily regressive because those who make the least spend far larger proportions of their income buying stuff for it. Most countries with VAT end up with complicated rules for exemptions for basic goods as a result, to try to balance it better.
It is not complicated to me: - food, books, medicine, ... -> lower VAT - cars, luxury items -> higher VAT
It's an incredibly complicated tax to apply, because the rules tend to grow to deal with more and more corner cases.
For example: Are jaffa cakes cakes or biscuits? It took a lengthy court case to determine that they are in fact cakes for the purpose of UK VAT [1] [2].
The reason for this case was that cakes are exempt from VAT as food no matter what, while biscuits are zero-rated in the UK only if they are not covered in chocolate. In the latter case they are considered confectionery, which is standard rated. Here's more on the complexities of this classification [3].
[1] https://en.wikipedia.org/wiki/Jaffa_Cakes#Categorisation_as_...
[2] http://www.hmrc.gov.uk/manuals/vfoodmanual/VFOOD6260.htm
[3] http://www.hmrc.gov.uk/manuals/vfoodmanual/VFOOD6200.htm