Don't count your chickens before they hatch
min viazese na panijirizis
In Greek Μην βιάζεσαι να πανηγυρίζεις
This idiom is a Greek proverb that warns against celebrating before the task is completed.
Example
"Μην βιάζεσαι να πανηγυρίζεις, περιμένουμε τα αποτελέσματα."
