I saw a good analogy of the tax system to computer code. The inland revenue express their intent of the tax system in code (or at least legalese). It's the job of accountants to exploit bugs in the tax system.

To misuse a famous quote:

"There are two ways of constructing a tax system. One way is to make it so simple that there are obviously no deficiencies. And the other way is to make it so complicated that there are no obvious deficiencies."