“a hundred days of sermonizing, one fart” → a metaphor for how something that one has put great effort into can come to nothing after even a slight mistake, much as a hundred days of serious spiritual study can be lost to the winds

a depressor septi nasi

(literally) a beautiful single red flower that blooms within a field of trees and grass / (figuratively) something unique that stands out among many other things

(literally) plan your day during the morning, plan your year during New Year's / early planning is the key to success