So we lose our natural instincts?
I don't think entirely, I mean some instincts and drives were deliberately created by God and are
meant to be things we take pleasure in, Why do you think Jesus gave examples of banquets and feasts when talking about heaven?
think about Genesis 1 and 2, think about that, that is what God intended for the world, and what He wanted to create.
Think about a loving God creating this, creating people, and then telling them "I give all this to you, have dominion over it, take care of my creation, but enjoy it" Things like the natural instinct to eat, and finding eating pleasurable, or drinking, and finding drinking refreshing, sleeping, and finding sleep refreshing (even God rested for the purpose of refreshment), even the sex drive, was created by God to be a good thing, and to be enjoyed, in the proper God given context.
What's going to be lost is primarily selfishness.
I dunno maybe I'm crazy, maybe it's all supposed to be worship of God and just falling on our faces and singing and being good little praise robots.. as awful of an eternity as that would be.
But I don't think GOD is that selfish or would enjoy that. Genesis 1 and 2 point to a God that made a place, made people and told them to enjoy it. It's like a gift, we just messed that gift up, it doesn't mean that God's taking that gift away, but rather restoring it. The one thing different, the one thing that seems explicitly taken away that is a good thing, is marriage, which could also mean sex but.. I don't know 100%.
It's based on a single verse, and usually used out of context.
But it is plainly stated, by Jesus
so.. can't throw it out either.