I have the same question..I used le tense imparfait as was instructed for habits, repeated action and description -all of which apply to this context...Then why is it wrong and why is passé composé used in this context ?? The action/ event was repeated every New Year's Eve and what the author expresses are his habits. 

Please clarify because such contexts always confuse me and I end up choosing the wrong tense.. Its getting very annoying as well as starting to affect my confidence :(