Jeff thought about a few things including how so many people smoke Tabaco, and how bad it could be for everyone... It even took his grandparents due to the cancer it probably caused. Well now he had a Cause and Effect package so he basically went to Tabaco and removed the cancer, premature aging, and all the harmful things it could do and instead added that it regresses you about 3 minutes per cig instead of taking away 3 minutes or something from your life. Jeff chuckled a bit and hit the reality alteration and then started coughing a little as he could smell smoke all over his room. Then he looked at himself and he looked a little smaller. Looking at the mirror he was looking closer to maybe 14-15 instead of 16. Jeff took a cig out of his pocket and lit it as he pondered how much younger he looked... and then realized he had a smoking habit.
Jeff thought for a second and considering how much culturally smoking was a thing, and that now there wasn't any downsides and arguably a bunch of upsides to smoking. Then he started hearing some arguments downstairs. He was curious and took a look and saw his mother who was looking much younger with a cig in one hand and a pamphlet on the other. In front of her was... Grandpa, and he reminded Jeff of what he looked like when Jeff was still a little kid.
"But Dad, don't you want to live longer and maybe see your great grandkids? This Tabaco respirator could even make you as strong as you were in your prime." Jeff's Mom said concerned.
"Bah! I prefer to smoke the way god intended with my smoking pipe. I'll even stoop to Cigars or those little Cigarette things, but I'm not funneling that smoke into my lungs with a box on my back and a mask! If I die because I'm not smoking enough that's fine by me." The old man said as he took some more puffs from an old wooden pipe.
Jeff went back to his room and went to his computer to look some stuff up... Turns out when you make a small amount of Tabaco make you younger it becomes incredibly more valuable, and people are figuring out more and more ways to make more and more of it. Nowadays there are treatments that can regress you years if you do it right by funneling as much Tabaco product as your body can handle... Although Jeff found it interesting that doctors still say you shouldn't smoke while pregnant... Albeit for much different reasons. So much had changed in the world just because of one... Well it wasn't really a little change now that Jeff thought of it. Still this seemed like an interesting world to be a part of Jeff though as he took a puff from his cig, opened his window, and saw a more hazy outdoor sky as more and more people had taken to smoking.