don't count your chickens before they hatch 

You should not assume that what you think will happen, will eventually happen. It's mostly used in cases where you would brag, plan, or make other deals before the event actually occurred. Originates from selling chickens based on how many eggs there is before you know how many eggs are viable. A few chickens may die, some may not hatch, and others eggs may break. Example: quitting your job or buying expensive items when your $1,000,000 sports bet looks likely but there's still two minutes more left in the game.

Hey Bob, you have to keep on playing hard. Even though we are up five goals with 5 minutes left, they can still come back. Don't count your chickens before they hatch.

don't count your chickens before they hatch by Crackle Dackle December 13, 2016