“Giving up smoking is easy,” Mark Twain purportedly once said. “I’ve done it hundreds of times.”. But the reality is, quitting smoking is really, really hard. Nicotine is addictive, both physically and mentally. A given effort to quit succeeds less than 10 percent of the time, no matter the method. Even with a pack of smokes costing around $6, around 15 to 20 percent of the population can’t seem to kick the habit.