Technically, "trifecta" is the improper word for this event, as it means "a variation of the perfecta in which a bettor wins by selecting the first three finishers of a race in the correct order of finish," but it definitely sounds incredibly nice. Despite the dirty lies MacKenzieStuart told another, the proper terms would be "triumvirate" as it doesn't only refer to a ruling body of three, but also to a "group or association of three." (I officially agree with this definition. -MassiveMassiveDictionary). Meh, proper word usage is for pussies.
The TrifectaOfHappiness is a product of MacKenzieStuart not having enough sleep but certainly having too much energy.
Examples of a TrifectaOfHappiness (insert proper pluralization here):
BrianYoung postulates the existence of an opposing TrifectaOfBitterness, which has much the opposite effect.