"With people you must become more like yourself to have a good relationship, but with God you must loose yourself first."
It seems I need to define what "good" means in this quote before I can understand what it is saying. I think "good" means something like "of God". If both "yourself"s mean the same thing, the only way I can think of to define "yourself" is with "what you desire to be".
I think it all starts with the second part of the quote. You must give your will to Him entirely, and He'll give Himself to you in return. Then, once you are living in this Love, it is possible for you to truly become all you are meant to be, all you desire to be, through surrender to God. "...plans for welfare and not for calamity, to give you a future and a hope..." God will become a part of every relationship you are in, and so they will be good because they will be "of God".
Surrendering to God's will results in growth intrinsically as well as extrinsically, which are both good. It means fulfillment of who you are as a human.