The light of the Lord does not automatically shine forth from us. Just because we are redeemed doesn't mean we are a lighthouse for those whose ships are running aground. We must "let" our lights shine, as Jesus stated.
If our light is barely visible, then we are merely ornamental and offer no real light to drive back the darkness. If we burn too bright and without wisdom, then we might offend those we are trying to help. Yet, if our light does not blind but instead provides a lighted path to the Savior, then we have accomplished a great thing. May our lights burn appropriately to always lead others to the Lightgiver.