How to Ruin a Good Day
A day that begins good and would otherwise continue that way if not for... what? This can really be seen in a whole lot of art, that precipitous cliff when rising action hits its impediment.
Be sure to describe the good day both relatively thoroughly and uniquely. Saying the ocean in Puerto Vallarta is 'blue' is not a description that someone will remember later. Be unexpected but also apt. Going off the deep end isn't always the best option, though sometimes bonkers really kicks up an otherwise OK piece to being a memorable one.