Take up running or something that makes you use your lungs more. Not only will it help clean out your lungs more, but also it will help keep you from going back to cigarettes. Pretty hard to justify smoking when you need your lungs for running.
Are all smokers slobs? I was. When I smoked, I threw buts on the ground all the time and dumped ashtrays in parking lots. Now that I am not a smoker I realize what slobs many smokers are.
Here is my worst low: In high school once, I ran out of cigarettes and had no money. I actually picked up a butt off the ground, lit it and took a few drags. Now that is getting pretty low!
What really kills me is how a smoker will not use the ash tray in their car because they don't want to get it dirty. Never mind their lungs, but that ashtray is very important.