Open Question: i know for a fact marijuana is safer than cigs and alcohol...?

but i smoke weed like either every weekend or every other weekend.. my parents told me they all did it when they were teens.. and they have good jobs now and are making good money. so why do people say its so damn bad? ive been smokin weed for like a year now and im still the same person. i wrote a 3 page essay baked and got an A on it and sometimes go to school high and do better , like i focus more on school. honestly f u c k the people that say its bad.. prove to me its bad!?