How does smoking affect surgery?

One of my co-workers and I were planning to have RNY around the same time. We're both going through the same doctor. Back in Sept I was told that I couldnt get cleared for mine until I remained smoke-free 8 wks and just reached that point yesterday. I know for a fact this chick hasnt quit yet. I still see her leave to smoke on all her breaks. She emailed me eailier today saying she has a date set for 12/28. Of course I still dont have a date yet and rather remain safe than sorry. What are the cons to remaining a smoker after RNY?

Ulcers.  I don't know all the ins and outs but some how continuing to smoke causes ulcers.  There are surgeons who won't even consider you until you're smoke free. 

My knuckle headed off spring went back to smoking post op despite this risk.  Of course all other smoking risks still apply.  I hope you stay off the smokes. 

I never understan people who have a life risking surgery to save and improve their life and then smoke, which is one of the worst things you can do to your body.