What would you say to someone offering you drugs or cigarettes? Has that happened?

Let me answer the second question first.  No one has ever offered me illegal drugs.  They have offered me cigarettes because in my younger and stupid life, I smoked.  This was before all the warnings came out and when the movie stars spent most of their on screen time with a cigarette in their hand.  It was cool and rebellious at the same time.  I am so happy that I quit before damaging my health.  My sister didn't.  She developed lung cancer and died last year.
As to the first question, I would say No Thank You.  I have already conquered the cigarette habit and don't want to start a new and more difficult one to conquer.  I don't understand willingly taking illegal drugs.  Putting yourself into a condition where you have no control over your body.  Making yourself available to anyone to do whatever they want.  Losing time that will never come again.  Damaging your health and physical appearance.  Eventually, becoming a criminal to support the habit.  I don't understand this.  Life is too precious to give away even a minute. 
When I want to rebel, I shall wear a red hat and a purple dress that does not go together too well and sit on the curb to eat my lunch.  Say what I really think and laugh only if I think it's funny.  Taking drugs and smoking cigarettes is what losers do.