It means that you got what you deserved.
Your mother told you to be sure to wear your hat and scarf because the temperature is dropping. You didn't do so and went out inappropriately dressed for the cold weather and caught a cold. Your mother then says, "It serves you right for not listening to me."
It means that you got what you deserved.
Your mother told you to be sure to wear your hat and scarf because the temperature is dropping. You didn't do so and went out inappropriately dressed for the cold weather and caught a cold. Your mother then says, "It serves you right for not listening to me."