Do not be misled: “Bad company corrupts good character.”
(1 Corinthians 15:33)

This scripture came in a daily devotion today and it's so true.  It's much harder to keep that smile on your face when someone you are with is down and frustrated.  Before you know it, you are joining the dismal mood, leaving your own uplifted mood far behind. 
I don't think "bad" is stronger than "good."  I just think it's easier to join the bad than to stand up for the good.  Keep that in mind the next time someone wants to mislead you or lead you astray.  Remember that the Holy Spirit will give you the strength and courage to keep your values intact, in spite of challenges or ridicule.