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
Theodotus	-	Ancient Greek (Latinized)
Youta	yo:-tah	Japanese
Seonag	SHO-nahk	Scottish
Hro&Eth;Ulf	-	Anglo-Saxon
Annabel	['ænəbel]
Daniilu	-	Old Church Slavic