I think the most difficult of decades, because life throws a lot at you and you have very little experience to understand what is going on. Happily, everyone you know is faking it the way you are. Too much temptation, too much alcohol, too much (you know what) and the next thing you know all those years you should have been studying and conditioning yourself for adulthood are gone and you play catch-up. I remember trying to prep my children, each individually, for what they would confront in college, sometimes successfully, sometimes not. The narrow, protected psyche of a high school kid thrust into a college setting where anything goes, and who are your friends? What choices will you make? If you raised them well, they'll come back, somewhere near your concept of the straight and narrow. But they're never the same after sowing their wild oats. Hopefully, they realize that your love and support never changes.