Greece has both loopholes (for ship owners / shipping companies, think Onassis) and corrupt tax collectors, but their biggest [OT] problem is the corrupt government that managed to greatly increase the interest on the country's dept so the banks could earn more - on purpose, I'm sure (good reading: famous composer and author Theodorakis about this => http://theodorakisfriends.com/news/the-truth-about-greece/).

Plus all the ridiculous feather-bedding of benefits to government and other employees that were clearly unaffordable.