To make a wish on seeing a shooting star

A response to someone wishing for something, conveying that merely wishing for something has no effect or is of no use.

Alternative form of if wishes were horses, beggars would ride

(often humorous) Whatever you say you wish for I will treat as a command and do straight away.

The desired outcome may not be as desirable once it has been attained.

(colloquial, archaic) A form of mild swearing used to emphasis the truth of an assertion; accompanied by if and the opposite of the assertion.

(archaic) second-person singular simple present form of wish