When you give up smoking the hardest part is not the cravings, nor the habit, it’s not even the lack of nicotine, the biggest barrier you have to face is other smokers! These "friends" don't want you to quit they don't want you to succeed, they want you to fail, they want you to continue to smoke just like them. All of them have tried to do what you are doing and they have failed they may not admit this but they have, they are envious that you can quit and they can’t.