This is the most egregious misapplication of scripture I can think of and it's just completely wrong.
First of all people who believe you can lose your salvation have to believe God's promise to keep them is a lie. John 3:16 has to be false. You do not "jeopardize salvation," if you could Jesus never had to die for ALL sin. It is immature and such undeveloped, deceptive thought to think scripture teaches you could lose salvation. Salvation is only God's to give, not anyone's to control at will. And frankly, quite arrogant to think one can give up, or lose salvation God has promised you.
What I think many of us Christians might not grasp is what HEAVEN is really like. Will there never be strife or struggle? I would like to hear the angels answer to this.
John 3:14 And as Moses lifted up the serpent in the desert, so must the Son of man be lifted up: (notice the punctuation)
John 3:15 That whosoever believeth in him, may not perish; but MAY have life everlasting.
John 3:16 For God so loved the world, as to give his only begotten Son; that whosoever believeth in him, MAY not perish, but MAY have life everlasting.
Where did it say that those who, when bitten by a snake, looked to the serpent Moses lifted up in the desert to be healed they were also assured of never being bitten again and therefore again in need of looking to the serpent Moses raised? It says that when bitten they had to look at the serpent Moses had raised up. Not a thing is said about their then being assured of never being bitten again.
MAY have is NOT the same as WILL have. Sorry, but John 3:16 in no way says anything about "once saved always saved" unless you prefer to twist it to suit your personal preconceptions.