Why do you sabotage my work like this?

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Why do you sabotage my work like this?
I do my job, for I know I have to.
I keep you able to live your life as you see fit, but why do you sabotage my work?
For 61 years I have worked, on every minute, of every day.
I woke up when you took your first mouthful of air, in a scream at the hospital, and I will be there when you take your last breath.
For 61 years I have worked without complaining, but I can no longer ignore your sabotage.
In 19 years every thing was great, everything was perfect, but then you started harassing me.
You started polluting me with your stupid choices, and habits.
I truly pity you, I pity your stupidity, I pity you stupid man.
In the next many years you woke up each morning, I am already awake, but you never notice.
You take a bath, and I go with you, but one again you ignore me.
You eat breakfast and ones again I am not noticed.
You get into the car, and I go with you, then you light cigarette and I complain.
“It is not good for you.” I say and your reaction is a hard cough.
“I told you so.” I say, but you just take another breath of death from your cigarette.
Then you go to work in the city and the smoke from your workplace, the factory, clouds your judgement.
After work you go home and drink a lot of beer.
I never complained though I worked 24/7 and all the thanks I got were your sabotage.
I don’t even think you knew that you sabotaged me, but you did.
Then you turned 30 and you kept up with working in the factory, and your smoking got worse.
I was still with you, but off course you still didn’t notice, though you slowly got more aware of me.
Ten years later you realised that I was not one you could survive losing, and you finally realised that I was not happy with what you did.
But you still tried to ignore me and all the trouble you were causing me.
Then you turned 50 and halfway to a hundred, you started to talk to my friend who lives next door.
“Don’t you die on me.” He said over and over again.
But my friend almost did die on us, luckily the doctors was able to save him, and some electronic devise keeps him alive to this date.
Then you reached 60 and my job was becoming impossible, you didn’t even stop your evil sabotage, even though it was killing both of us.
Now it is one year later and I finally quit we had some good time together but I can no longer work with your sabotage, you will have to get a replacement for me.
The next day I saw you walking along, pulling a little trolley, on the trolley there was my replacement a large bottle of oxygen.
Who am i?
I am the broken lungs of the smoker John.