The Torah gives a serious warning as to how one might get into a progression of one bad deed leading to the other.
Rashi emphasizes this by way of the order of events presented at the end of ויקרא. There is a warning to observe the Shmitta year and to have the faith that Hashem will provide for his financial needs. This is followed by one’s lust for money that will cause him to price gouge. As a punishment for his greed, he will first sell his movables, and then be forced to sell his field. Things could get so bad, that he might even be forced to sell himself into slavery, after being forced to take loans with interest.
Over the years, I have heard numerous stories, from a wide range of individuals, as to why they they stopped being observant. The recurring theme from many of these people, is that they really didn’t intend to stop observing. It just kind of happened.
Sometimes it was blamed on the army, where they gradually became lax in observance, because nobody else was doing it. The same story has happened to university students. Somehow they went along with the crowd, and before they knew it, one thing led to another, and their religious observance was no more.
I have also found that when people took the apparently trivial step of removing their Kippa in public, much more came off than the Jewish skullcap. The three pillars of Judaism, Shabbat, Kashrut, and Family Purity, all became compromised with the removal of the Kippa.
The realization must be that one thing leads to another. We must have a strong resolve not to compromise that which we hold dear. There are so many temptations that could lead us astray. We must not let this happen.