"Whoever comes to me and does not hate father and mother, wife and children, brothers and sisters, yes, and even life itself, cannot be my disciple. Whoever does not carry the cross and follow me cannot be my disciple."
He didn't mean literally "hate" (in the sense of "hostility and loathing) or even "ignore" or "be indifferent to," but He did mean that one should prefer the way of Christ to all things, even prefer it to this life itself.
If one had to choose between Christ and one's father's or mother's wishes, or one's spouse's or childrens' wishes, or the clear demands of our own "reasonable" self-interest --- we should go with Christ and leave the rest behind.
So I would say "detachment" in the sense of a cold, hands-off attitude toward all things, is bad; but "detachment" in the sense of putting Christ, always, radically first, is good.
Does that make sense?
How much we want to smooth the edges off of this one! It is indeed a hard saying. One of the hardest!
In other words I think I need to work on my interior life with Jesus, if that makes sense.
Despair I think comes from not working on your interior life. That inner dialog, yes dialog with Christ. As a priest told me, when you are so busy talking to him, he does not have time to answer.