set (oneself) up for a letdown

To set one's expectations so high that one will inevitably be disappointed by the outcome. (Sometimes hyphenated as "let-down.") I know you're really excited for this movie to come out, but I think you're setting yourself up for a letdown. John was so convinced that his relationship with Mary was perfect that he set himself up for a let-down in the long run.

Common Names:

Name	Pronounced	Usage
Sierra	see-ER-ə	English (Modern)
Justinas	-	Lithuanian
AmÉRico	ah-ME-ree-ko (Spanish)	Spanish, Portuguese
Young-Hee	yung-hee	Korean
Toiba	-	Yiddish
Fillin	-	Irish