There are a lot of smokers who hate stoners, and won't mention their mj use to casual acquaintances. And it's certainly not for everybody, especially at higher doses or potency.
A drug more benign than alcohol.
Smoke too much, take a nap.
Smoke too often, cut down and get sharp again.
Drink too much, you get flu symptoms.
Drink too much too often, you get a new liver, or die.