Weed is really high on THC nowadays, which can easily make you panic or make you paranioac. As for most people it's bought illegaly, it is hard to know exactly what you're consuming, and even a cautious guy like me can make errors (I took several kind of drugs before that, and mostly which people consider stronger stuff).
I don't think it should be illegal, but be careful with what you're smoking, which quantities, where, and please don't talk about it like it cannot be dangerous and it's the perfect solution to relieve stress/relax.