Sure you did! Nice excuse anyway, it's cool being ignorant huh? (:
In other hand, the arguments for it are many and varied, its a relaxant, it has medicinal properties, many products can be made from the plant such as paper and cloth, the plant itself is one of the best plants to stop soil erosion, its effects are far less harmful than alcohol and many legal drugs.
The argument against that it is a gateway drug is unfounded. The only reason why cannabis can ever be seen as a gateway drug is because it is illegal and thus it is sold by the same dealers who sell herione, cocaine etc. If it is legalised it can be controlled, taxed, etc.