Here's the thing about opinions you can only have them on theory's idea etc. on facts you can not because they are well facts. So to say weed is bad or it kills because of something you heard or a personal opinion is bias and untrue. All study's including the study commissioned by Bill Clinton has proven weed to not have any direct negative effects on your mental or physical health. However knowing this depending on how you smoke the weed it can still be harmful to your lungs. You should avoid blunts and joints. And either use edibles or glass bongs and bowls this will avoid the damage to your lungs.