Nicotine does not give you the ability to perform complex tasks. It reduces appetite and raises the rate that food is changed to energy. Nicotine causes addiction. Nicotine is found in cigarettes. People who start smoking often can't stop because of how addicting nicotine is. People who stop usually experience severe side-effects such as headaches, sweating, severe insomnia, and many more. Usually in the U.S., 400,000 Americans die from smoking each year. It usually causes cancer and other health concerns.