Bad company
Mixing with bad company is what every youngster should avoid. The reason is simple. In such a company, sooner or later the youngster will be exposed to activities that are possibly unhealthy, unwholesome, antisocial, dishonest, illegal or even criminal. Once exposed, the negative effects can last a long time, perhaps for a lifetime.
The company you keep will determine largely what you do, how you think and where your life will proceed. In other words, keeping bad company will eventually ruin your life.
Bad company is not hard to spot. For example if your friends smoke, then chances are you will catch on. If they take alcohol or drugs, chances are you will be tempted to give them a try. One try leads to another and it will not be long before you are hooked. Alcoholism, lung diseases, AIDS or a miserable life may in store for you. So for your own wellbeing, it is better to avoid such friends. There is no need to make enemies of them. Just avoid them.
If you mix around with friends who vandalize public property, shop-life, scratch cars or extort money, then it is time to call it quits with them. Such behavior will lead to more serious offences and it is a matter of time when you are on the wrong side of the law. Get out quick before it it too late.