Everlasting life
I grew up, as most Americans arguably have, with John 3:16  "For God so loved the world that He gave his only begotten Son, that whosoever believeth in him shall not perish, but have everlasting life."

Christ is the son of God.  Check.
God sacrificed his son to wipe away all our sins.  Check.
Because of that we get to live forever, as long as we are saved.  Check.

This is sounding like a pretty good deal so far.  God loves us so much that he gave up his only son for to allow us to live eternally.

How good a deal is this?
Throughout history, countless fathers have given up their sons for one reason or another.  (slavery, expansionism, freedom, etc)  So, this is a sacrifice we can relate to.  It sounds really really serious, so the benefit we draw from it gets  some credibility.

He "gave" his Son.  It was the ultimate sacrifice.

He's obviously pretty serious about Salvation.

But God didn't give up anything.
God got his son back three days later.

How much of a sacrifice is that?  "I and my son both live eternally, and I gave up a long weekend with him.  That should show you how much I love you all."   Honestly, that just doesn't seem all that magnanimous.

And God is not even capable of sacrifice...
To sacrifice something is to give it up, to not have it anymore, and not be able to replace it.

God can make other Sons if He wishes.

"For I so loved the world that I clipped my fingernails."  It just doesn't have the same ring to it, but it would presumably take about as much effort for God to create a new Son if He so desired.

The end result?

If we believe that He gave up His Son, we get to live forever; but he's incapable of giving up his son.
If the sacrifice on His side doesn't happen, does that mean that the benefit on our side can't happen either?

It's a tad disturbing.