There are a variety of synonyms for the phrase "hard to please," including the words "demanding," "choosy," and "fastidious." These words all convey the sense that someone is difficult to satisfy or satisfy completely. Other possible synonyms for "hard to please" might include "critical," "picky," or "fussy." Each of these words emphasizes a different aspect of someone's tendency to be difficult or demanding when it comes to their preferences or expectations. Ultimately, the choice of which word to use will depend on the specific context, as well as the tone and style of the communication.