Most other illegal drugs, such as heroin, crack, and cocaine, are very addictive. This means that someone with an addictive personality ,or someone that has no worries or knowledge of side effects of the addictive drug they're about to do, starts regularly taking an an addictive drug (heroin, meth, or cocaine), the person will want to keep taking more of the drug, even if it is making them sick with or without it. Legal drugs such as tobacco, caffeine and alcohol are also found to be addictive, tobacco the most. Tobacco can be just as bad, if not, worse of an addiction than methamphetamine. The tobacco user will typically go buy some more cigarettes or pick up used butts to smoke if they run out. If the meth user runs out, they have no easy legal source to get it, and if they have no money they can't just pick up a dirty second hand "meth butt" (no such thing) off anywhere on the ground. The addiction is as strong as tobacco, that they "need" it, so many of them end up breaking into people's houses and cars to steal money and possessions to trade for more, which tobacco users do not tend to do. Tobacco users do tend to smoke much more often, however.