Caffeine

Sometimes I am insomnious because of caffeine. I know that I won't be able to sleep well if I have cups of tea or coffee, but I ignore it. No matter I drink them in the morning or at night, the side effect comes whenever I want to sleep. Some people won't be affected by caffeine. I hope I can be like them, and then there will be no need for me to worry about my sleepless problem.