Losing Salvation?

1. What can you do to lose your salvation? (keep in mind these are hypothetical questions as far as I'm concerned as I don't believe one can 'lose' salvation)

If a Christian can lose their salvation, I imagine it is through some act, mental or physical, that transmutes one from salvation back into damnation. Nobody believes God capriciously revokes salvation to obedient and believing Christians. Usually it is a Christian who has stopped believing or in more severe theologies a Christian who has sinned too much. This begs deeper questions:

What are we saved from? If we are saved from the penalty of our sins through faith in Jesus Christ it would seem a bit odd that such sins would then be the means of revoking our salvation. Perhaps we are only forgiven of past sins until salvation, but after we enter that relationship we become bound to sin only a certain number of times before that forgiveness turns into wrath again. It would ask again, what is it we are saved from in such a scheme? Salvation is not salvation if we've got to pay it off once we've leased it from God by obedience.

As for the Christian who has stopped believing we also ask some questions on top of this. What did they believe, and with what do they believe? We surely don't want to think every act of belief is what the Bible calls faith that justifies. If someone assents to the existence of God and Christ and then suspends that assent at some point later in life, surely we would question not their final salvation only, but their initial salvation. Was the first state of faith the Biblical definition we see in Scripture that"God will work good for a person no matter what and save them ultimately in the day of judgment by the redemption in Christ." Now what if a person were to hold that doctrine and then leave it in the sense of "God surely could work good for a person, but I don't think he is working good for me." The misfire in faith is not about the Giver but about the receiver in this sense. Damnable low self-esteem? Or is God better to this person even than their own self-receptiveness could imagine? We are in gray space here, but I'll wager an idea just for the sheer fun of it.
Justifying faith is imperfect. Were it required that it be perfect, none would be saved. Even weak faith saves. Even a mustard seed of it throws the mountain gurgling into the sea. Because faith is not the savior, the Object of faith is what saves. So if the faith is in God, even a temporary lapse of faith would not be the justifying agent in the equation. I could be wrong, and we could debates texts and passages, but I'm thinking out loud right now.

So what can you do to lose your salvation? Fail to receive it initially is all I can see. Can a person outsin grace? Can a person believe too weakly in God that He is able to save? We know they can believe amiss, but too timidly? I don't know that I'd go there from here. A new scheme of justification would have to be adapted to for me to connect the dots that way. And I'm not moving there as of now.