I'll bite... Depending on the drug you can * Become unpredictable and therefore dangerous to your surroundings * Become aggressive and/or violent * Decrease

I'll bite... Depending on the drug you can * Become unpredictable and therefore dangerous to your surroundings * Become aggressive and/or violent * Decreased cognitive abilities can make you susceptible to bad decisions * Slurred speech and thinking can make you unable to help friends, family and others should they need you to. That's just off the top of my head, please note that some of the above also applies to legal drugs.