come back (down) to earth
To regain a realistic view of or attitude about something. Those newlyweds think that marriage is utterly blissful, but they'll come back to earth soon enough.
come back (down) to earth (or bring someone back (down) to earth)
return or make someone return suddenly to reality after a period of daydreaming or euphoria. 2003 Guardian When you start to believe you're in with a shout, the big boys have a nasty habit of bringing you down to earth with a bump.