This is something I'm guilty of doing almost every day, so I needed this wake-up call. "You want to wake up in the lighter stages of sleep," Dr. Dasgupta told POPSUGAR. "If you hit the snooze button, which is very tempting, you can go into a deeper stage, and when you wake up from a deeper stage of sleep, or from REM sleep, you could get something called sleep inertia. Sleep inertia means it's really hard to get the day started." He likens it to getting a boulder rolling from a complete standstill. In other words, it's not an ideal state to be in, especially when you have a busy workday ahead of you.