Is saying what you think worse than just thinking it?

Many people would say yes, but in actuality it is no.  God knows our thoughts along with everything else that we do (Psalm 94:11).  So, if we have thoughts about someone or a situation that would be considered wrong then God still knows about it and it is still a sin.  Now if we do keep it to ourselves then there are less consequences from a worldly view, such as the other person not knowing what we truly think of them.  However, given enough time our thoughts will come out verbally because what is in the heart comes out of the mouth (Luke 6:45).  The best way to avoid this situation is to keep our thoughts pure and righteous, then our words will be that way too.