John 1:4-5

I was greatly delighted to find some of your children walking in truth, just as we have been commanded by the Father. Now I ask you, lady, not as if I were writing to you a new commandment but (simply reminding you of) the one which we have had from the beginning, that we love and unselfishly see the best for one another. 

This world needs us to show love and kindness to everyone we meet, whether Christian or not.  Showing love does not mean we approve of bad behavior.  Showing love means remembering that Jesus first loved us and died for our ugly sins.  When we meet people having a bad day, show them, love.