It's easy to make a false memory. All you need is a friend and this list of words. Then ask your friend to remember as many of the words as he or she can.
Most people can remember about half the words.
The reason some people remember the word sleep is that words like bed, snooze and doze remind them of sleep. For example, witnesses might see a crime and think that the perpetrator resembles somebody they have seen in the neighborhood once or twice. Later, these witnesses might testify that the person they were reminded of actually committed the crime. That may sound farfetched, but it has happened in dozens of cases that were later overturned by DNA evidence.