I believe it's all in how you say it. example: I say " that's nice" often. can mean : -that is nice - I wasn't listening - shut up :/ -I hate your guts -fook off , I hate your guts and or youe face - HUH? I pick how say it then. Final answer.... that's nice of me :)
I also think it is most important in 'how' you are saying something. The 'what' doesn't matter as much b/c it is all about how you intended to interact with that person... how you intended to be with them, if you were say revealing sad or upsetting news but did it with grace and kindness, it would be much more accepted and peaceful to the person than if done with fervor or drama. Great question.