Gerald Durrell, in "My Family and Other Animals", tells how as a child he let his sister take care of some orphaned baby hedgehogs while he was away. He told her to be strict with the milk, not to overfeed. When he came back, he found that she'd fed on demand and they'd all died, because they couldn't stop demanding.
We live in a society that has plentiful cheap food, readily available and aggressively marketed alcohol, easily obtainable tobacco, easily found illegal drugs (and glamourised a thousand times by the media), computer games everywhere. It's surprising that anything gets done.
Some argue for decriminalisation of "harmless" drugs like cannabis, contrasting it with the undoubted dangers of alcohol. I agree with them in a way they won't like: alcohol is far too easy to get hold of.
Libertarians overestimate the amount of control we have over our behaviour, I think. Sartre argued stubbornly against the theory of the unconscious, because it undermined his philosophy of existentialism. I incline to the Buddhist analysis, that we continually form strong attachments and only the most determined can break the chains. Few manage it on their own. Some would say only 5% per year break free of alcohol, and perhaps a far smaller percentage stay off it permanently.
In our debates on liberty, should there be some discussion about restrictions that make us more free?