It's always encouraged to get a full 8 hours of sleep, but the quality of that sleep is just as important. Waking up repeatedly throughout the night can put anyone in a bad mood the next morning, but one study set out to prove that disrupted sleep indeed causes mood problems. A research group from John Hopkin's University enlisted 62 individuals with no known sleep issues to participate in a special lab study. The participants were assigned a different kind of situation by random; either sporadically interrupted sleep times, continuous interrupted sleep, or sleep with no interruptions whatsoever. Each group was given the same amount of time to sleep. By the end of the study, researchers concluded that it was a combination of both the time put into sleep and whether or not the individual was disrupted. Participants who were occasionally disturbed or completely interrupted while sleeping experienced far less moments of actual "deep" sleep, which in turn led to a negative mood the following morning. Participants who lacked sleep also reported to have less energy overall, a lack of friendliness toward others, and a decrease in empathetic feelings.