ATHENS—Behind the budget crisis roiling Greece lies a riddle: Why does the state spend so lavishly but collect taxes so poorly? Many Greeks say the answer needs only two words: fakelaki and rousfeti.

Fakelaki is the Greek for "little envelopes," the bribes that affect everyone from hospital patients to fishmongers. Rousfeti means expensive political favors, which pervade everything from hiring teachers to property deals with Greek Orthodox monks. Together, these traditions of corruption and cronyism have produced a state that...