Wearing jeans arguably hastened the end of the Soviet union: https://en.wikipedia.org/wiki/Jeans_Revolution

Alcohol is haram. I hear the attitude towards Jeans in SA is now more lenient but less than a decade ago would get you in hot water with the religious police.

You get the gist of it. The moment they leave that country many of its young people act very differently in ways that would not be allowed/frowned upon back home. What is up with that?