True honesty often comes across as rude. If someone asks me what I think of their new carpet and I think it looks like shit, I'll tell them just that. Saying "I don't like that carpet" would feel dishonest as it's only limited honesty. (being honest about the opinion or thought, but not about its intensity)
Honesty is not hypocrisy. In a world where "he's gone" means "he's dead", honestly is almost always brutal.
Especially when honesty matters the most when people don't want to hear what you're saying. No amount of sugar and paraphrase will make a nice "I don't want to talk with you".