Kindness matters. Practice kindness.

Actually you can practice being both! Trust Anne Lamott to come up with a good-sounding false dichotomy. Your buddy Adam Grant even says that the rarest and most valuable person in any team is the one who tells you the truth you need to hear. That is because most people would rather not run the risk of hurting themselves -- risking their own self-image or reputation -- to truly help others. Is that kindness? Or is it cowardice? Of course you want to deliver the truth in the kindest way that will be effective in that particular situation -- you don't want to be a dick if it's not necessary -- but sometimes you have to be cruel to be truly kind.

In computer science we call this an inclusive or, because you can do both.

Excellent point, HalibutBoy. Thanks for chiming in.