Yesterday I was inundated with bad thoughts, and I was desperately calling up all my little tricks to escape but was not fairing well. B"H one thing snapped me out of it, I thought of what I would look like if I actually went full out with bad thoughts and even acted upon them G"F, and I got a pretty scary (-i.e. utterly disgusting) image, and with that B"H I got right out. This is probably the same with many things, like drugs, hitting up even once has to be understood in the context of the big picture - what is the tachlis (-end-ultimate purpose), to get high, and if this high is a good thing, so it would be done more and more, ultimately ending in the person G"F being a junky, hence this high is actually a piece and part of a very nefarious ordeal. The desire for money on the other hand, although we know that our Sages obm revealed one who has a hundred wants two etc., even still there is a certain satiation point or goal where a person is providing for his needs, just like eating. The highs from drugs or the gratification from sexual desires are not the same, because they are not intrinsic to a persons life -- a person does need highs and does (if he is not a tzaddik) need a sexual outlet, but those have a kosher scheme which in and of itself means that they are are being used intrinsically for his life, and not some external quest. Quests for holy highs are very intrinsic and satisfying, yet even they are surrounded by great dangers, for at every new level one is faced with more powerful needs of gratification, and if he is not constantly on guard and aspiring to the holiness he has become accustomed to, he will be hit very hard for vitality from the other side G"F.
There's a great more to be said about all of this, and of course it is much better to read about these things directly from the holy teachings of Rabbainu, but B"H it is good to at least write a little something and not let it go unmentioned.
May the Holy Merciful One G-d help us have holy thoughts and only holy thoughts and holy consciousness.
Na Nach Nachma Nachman MeUman!