I don't smoke but have had friends ask me, when experimenting with smoking, what's wrong with just trying it once? "It's not like you'll get addicted by trying it once." But I am afraid to smoke, or even to experiment smoking, after having read the Qur'an. When you look at an addicted smoker, what do you see? It's not just someone fulfilling their instant desires, being a puff away from all sorts of cancers, wasting money on an addiction, it's deeper than that:
25:42 He would have led us far away from our gods if we were not so steadfastly attached to them.” They will know, when they see the doom, as to who is more astray from the road.
25:43 Have you seen the one who has taken as god his own vain desire? Could you be an advocate for him?
25:44 Or do you think that most of them really hear and use their reason? Nay! they are but like cattle. Nay, they are farther astray. [The cattle at least follow the Divine laws instinctively]
It's a similar story with pork. Even if a piece of pork can be reasonably determined to be clean, eating it in spite of God clearly commanding us not to is holding our ego above the Qur'an. For me the admonition from eating pork is a test of humbleness, especially if we reach an age where we can be sure that a piece of pork is clean.
The Qur'an generally admonishes all mind-altering and addicting substances:
5:90 O You who have chosen to be graced with belief! Intoxicants and gambling and games of chance, sacrificing animals on stones (altars of idols) and forecasting the future by such means as arrows, raffles and omens (all) is an immoral handiwork of Satan. Refrain from it that you may prosper.
5:91 By means of intoxicants and games of chance Satan, your rebellious and selfish desires, incites you to enmity and hatred among you and hinders you from being conscious of God and following the Divine System. Will you not then abstain? [2:219]
5:92 You shall obey God and obey the Messenger, the Divine System that the Messenger has established, and be careful in this regard. If you turn away, it will be to your own detriment. Know that the duty of Our Messenger is just to convey the message clearly.