Pavlov is famous for his research on classic conditioning. Most are familiar with “Pavlov’s dogs”; he used them to discover that unrelated stimuli can be used to elicit certain responses from test subjects. In his study, he rang a bell right before feeding time and dogs, expecting to be fed, would begin salivating; he even measured the increased salivation (what fun!).
In later studies on conditioning, however, the question arose, “Can reverse conditioning be successfully achieved?” In other words, once the conditioning has been ingrained in the subject, can it be undone? Well, as it turned out, “backward conditioning” was ineffective when compared to “forward conditioning.” So, it is much easier to create a habit than to break it.
When our peers entice us with a “try-it-you’ll-like-it” temptation, just remember that it’s easier to get into sin, its suffering and its sorrow than it is to get out. “Scars are souvenirs we never lose; the past is never far”  are lyrics that ring true. “I’m sorry” and “my bad” does not relieve the embarrassment and shame of a word or a deed that falls short of the mark.
If we would only listen to our Lord, we could spare ourselves untold misery and regret. Often starting with the phrase, “Be not deceived,” He gently warns, “God is not mocked; for whatever a man sows, that he will also reap” (Galatians 6:7; cf. 1 Corinthians 6:9; 15:33; James 1:16).
Words and actions have consequences and are much better thought through prior to their expression. Jesus, even when it comes to following Him, warns: “count the cost” (Luke 14:26-33). We need to especially teach our young people about the “Humpty-Dumpty Effect”; some things broken cannot be “fixed.” Moving forward is easier than backing up, so move forward… with the wisdom that is from above.
 Carr, H. and Freeman, A. (1919). Time relationships in the formation of associations. Psychology Review, 26(6). 335-353.