Marijuana is no worse than alcohol. The government and media in the U.S. have done a good job of brainwashing the public into thinking that weed is the devil, and it can kill you, etc. etc., just because it's illegal. See: TRUTH ads. Might as well call them LIE ads.
They also make you think that it will indefinitely lead you into harder drugs. This is also false, for the most part. Most people I know that smoke don't do any other drugs, with the exception of alcohol. I myself smoke weed and drink in moderation, but I'm proud to say I've never smoked a cigarette in my life, nor do I plan on it. Hell, weed is better for you than nicotene is...plus it gets you high, while nicotene is really just a ****ty version of caffeine. And you won't get addicted to marijuana if you use a little common sense and willpower. Basically just tell yourself, "No, I don't need to smoke today, I'll just do something else." And it's solved. But as some of you might know, it takes a ****LOAD of willpower just to get over a cigarette addiction. It's mostly a physical addiction, with withdrawal, whereas with weed, it's mostly just a mental hurdle. Kinda like getting yourself to work out every day, or to stop eating junk food. It can be done, you just have to DO it.
I think in general, weed is probably about as harmless as caffeine or alcohol. That doesn't mean you should smoke every day. If you smoke even about 3 times a week, you will start to notice a sort of "haze" in your thoughts. You will become a little slow to think, if you know what I mean. You won't become dumber, you just won't be able to think very quickly, and you will lose some short term memory as well. Because of this, I only smoke a few times a month, at the most, cause I like being able to think quickly and clearly. And keep in mind that the "haze" is really due the THC coating your brain cells. It does NOT kill your brain cells like the propaganda machine says it will, it just weakens them. When you stop smoking, you will notice that you can think much more quickly, and you aren't so lazy either.
Just for the fact that it does make you lazy and slow to think, I don't smoke very often.