The correct answers are: Life in the 1980s was wonderfully chaotic and full of neon. The life of a billionaire is not as simple as it looks. I was lucky to receive an excellent education in Switzerland.

• Life in the 1980s: Even though it has a prepositional phrase ("in the 1980s"), "life" here refers to the general human experience during that time, so it takes the zero article.

• The life of a billionaire: When "life" is restricted by an of-phrase pointing to a specific person or role, it requires the.

• An excellent education: Abstract nouns related to learning and knowledge (like education, understanding, or knowledge) take a/an when they are modified by an adjective to describe a specific quality or type. Using "the" here would incorrectly imply a specific, previously mentioned education.