People generally mix up good and nice. Being good is doing the right thing, even if may hurt (yourself or the others). Being nice is lying to everyone's face to tell them what they want to hear. If Jesus was nice, the world would love him. But the world doesn't, because Jesus is good, not nice.

This is a major problem today, that I see often especially with parents. They think they should be nice to their kids, never raise their voice, never tell them no, encourage them to do and try anything. That's just not how you educate someone, and that's not how God educates us either.