You would think an emergency room is a place to get medical care quickly, but plenty of us know the feeling of waiting for hours even if the place doesn't seem busy. This video helps to explain why.
Part of the reason is triage: the concept of sorting people according to how time-sensitive their problem is. Even if you have a serious illness or injury, if you're unlikely to get worse in the next few hours, you won't be at the top of the list. "First come, first served" doesn't apply here -- the person who walks in an hour after you might see the doctor before you do.
Another part of the reason is simply that the emergency department is connected to the rest of the hospital. If there's a wait for a certain room, machine, or specialist, that can affect people throughout the hospital -- including in the emergency department. Watch the whole video for more on how emergency departments work, including how to get the most out of your discharge instructions when they finally let you go home.
Why Am I Waiting in the Emergency Department? [Doc Mike Evans]