There's this thing coming around saying that every stoner is lazy, doesn't do anything all the day. Well in my opinion laziness isn't something that cannabis is responsible for, the person smoking it is, if the person is lazy already, marijuana doesn't change that, and if the person is active, he'll will probably active even after smoking. Of course the strain of the cannabis smoked may be the the "sedative" type, especially the really strong ones, do put you down, however there are strains that are complete opposite, making you motivated and it makes you want to do things. Then the unemployment, I know quite a lot of people who used cannabis and had a perfectly normal lives with good jobs etc.
Anyway, that's my 2 cents for this issue.