Nothing at all. Weed does not harm the body and is no were as bad as what is currently still legal like caffeine, alcohol, and tobacco. If it becomes legal I will stop drinking tbh. The only downside I’d say is the impairment effects but the affects can vary per person and their tolerance level. Me personally for example I can’t drive high, but some can just fine. Apparently a lot of research has been made and is still being made in marijuana research. Discovery of how different strains affect users, various cannabanoids within the plant, and the mental affects per individual are reimagining how people think about marijuana. There will be some folks still stuck in their old ways to keep it illegal but I believe that this coming year or the next will be when America will be able to enjoy the benefits of marijuana legalization and decriminalization.