The Passover for Jews and Christians is a synonym for quot; party quot;. It is the commemoration of the departure from Egypt of the Israelites, who fled a massacre safe and on their way to the promised land, the future Israel. Hence the expression to be happier than a Christmas.
Locution adverbial so that indicates that someone is happy, satisfied in great degree. Using a comparison or analogy to strengthen the fact that happiness. In this case " Easter " denotes the time of Easter; but, in turn, connotes spring: REBIRTH of nature, flowers, birds, light, colour, perfumes. Nature revitalizes. Overcome that gratitude and happiness is a hyperbole, a mode of sobrepujamiento.
