People who sleep soundly often take the ubiquitous activity for granted. They are unfamiliar with the endless wakeful nights of the tormented insomniac. But most people have experienced insomnia at least once in their lives—a terrible night when no amount of tiredness can shut down an active brain. I’ve had many of these nights in my life. They often happen in times of stress, when my troubles occupy my thoughts. It took a few years of regular insomnia before I started really researching possible causes, from my diet to my brand of foam mattress. I was surprised to find some clear criminals among the commonly-used substances in my daily life. I didn’t realize that my lifestyle choices were sabotaging my sleep! They may be sabotaging yours too. Here are some common culprits.