"Be soft. Do not let the world make you hard. Do not let the pain make you hate. Do not let the bitterness steal your sweetness. Take pride that even though the rest of the world may disagree, you still believe it to be a beautiful place." - Iain Thomas
You do yourself no server by remaining closed and unhappy because life is going to make you so anyway.
It may take some bravery but life is more fulfilling when you allow yourself to remain open and loving. Happiness is not a sin and you are not a lesser person by choosing to be happy when perhaps apathy is easier or more accepted. Life is short and you will find too few reasons to smile if you go looking for the perfect excuses. Allow life to fill you up and be rewarded.