system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 why is smoking bad for you specifically and emotionally what can it do to your body? How long would it take to smoke for it to hurt your body?
gpt
Gonna assume you mean smoking tobacco.

Tobacco smoke contains carcinogenic compounds. These are chemicals that attack the DNA in your cells. 99.9% of the time that just results in the cell dying, and your body replacing it, but a small fraction of cells will become cancerous and start multiplying. Every cigarette is basically playing the cancer lottery. You could get cancer from the first one you ever smoke (*very* unlikely) or you could smoke 50 a day for 40 years and never get cancer (also *very* unlikely). 

Tobacco smoke also contains tar and other chemicals bad for your mouth, throat, and lungs. Smoking *will* lead to emphysema, and other lung disease, causes high blood pressure, and seriously increases your risk of heart attack and stroke. It also kills your senses of taste and smell pretty effectively.

Smoking is never good for you, and it's a habit you should definitely avoid. Trust me. It's inconvenient, expensive, and a total bitch to quit. 

Edit: Nicotine is a seriously lame drug anyway. You get a little buzz at first, but after you get tolerant to it you get nothing at all except a constant craving to go smoke.