Okay let me say this first off, I smoke weed alot. And I mean ALOT. Now some people will say that "Weed isn't a drug", which is bollocks. But can you become addicted to it, not physically. Some people can grow a mental addiction, where they seem to "need" it to go through their day, even though if they stopped they would be perfectly healthy.
Now contrary to popular belief SMOKING marijuana is bad for you. The human body is not meant to take in any type of smoke into the lungs, only oxygen. So when that guy tells you that smoking a joint is good for you every now and then, he's wrong. It can kill your lungs if you use it excessively over long periods of time.
There are however safer ways to partake in the use of Marijuana. Ways such as vaporizers, brownies, and boiling (though not recomended unless you really know what you are doing) are all methods that allow you to use, without damaging your lungs. Instead they will only temporarily damage your judgement.
Now with brownies or baked goods, be careful. Be sure to only eat half of the product first, wait 15-30 minutes then if you feel you can handle yourself eat the rest. Now be warned about baked baked goods, they contain a good amount of "love" in them, approximately 1-2 grams of love to be exact.