Andrew Bosworth, engineer at Facebook:

Being kind isn’t the same as being nice. It isn’t about superficial praise. It doesn’t mean dulling your opinions. And it shouldn’t diminish the passion with which you present them.

Being kind is fundamentally about taking responsibility for your impact on the people around you. It requires you be mindful of their feelings and considerate of the way your presence affects them.

Great, honest story about a very common problem. Kudos to him for sharing.