Nicotine makes it difficult for a smoker to quit using cigarettes primarily because it creates a strong physical and psychological dependence. When an individual repeatedly consumes nicotine, their brain begins to rely on it to function normally, leading to withdrawal symptoms when they try to quit. These withdrawal symptoms can include intense cravings, irritability, anxiety, and difficulty concentrating, making it challenging for smokers to stop using cigarettes.
None of the options provided directly address this dependence or withdrawal aspect effectively. However, the closest answer related to smoking difficulties would be the statement about "Many people experience intense headaches," as headaches can be a symptom of nicotine withdrawal.