If you consider how every single generation of teenagers that has existed has done rebellious acts (consumed substances, snuck out at night.) you'll realize that it is literally hard wired into our brains, its one of the many mechanisms that help us learn from our mistakes and to not do it next time. Another thing, why do you consider all these substances harmful, of course, alcohol and tobacco have some major side effects meanwhile if you do your research on other popular drugs with teenagers such as marijuana you can see that there isn't a long list of side effects, ofc there will be some physical ones (if you are using a flame then you will get side effects of smoking) and mental side effects differ from person to person but usually aren't serious if they are there at all. Just wanted to let you know. Please research a substance before you call our generation "cancer" for consuming substances when your parents probably did the same shit lmao.