I am sure you have all heard the "If you build it, he will come" well the ER is of the philosophy... If you come, we will see you. It would be nice to close the doors when the ER is full or when staff has reached its limit but there are no limits in the ER. You work as hard and as safely as you can, let people know when you are stretched to the max and hope to see a light at the end of the tunnel. We used to be able to divert ambulances when we were at breaking point but even that is now a "no no" per the hospital system policy that I work for. We are in the business of healthcare 24/7 and as such we see, treat, and admit based on each pt needs... not to pick on the nurses.
I still stand by the fact that every department is different and can vary from hospital to hospital. Every department will have its good days/nights and also bad days/nights, its simply the nature of the beast. The best way to get a feel of the work atmosphere is to talk with the people that actually work in that department or shadow someone.
For GilaRN: ER patients are not categorized quite as "simply" as you may think, and some patients can be very complicated and time consuming while we find out what is going on. They do not come to us with diagnosis and orders to follow, we often have to scramble to have all that so "simple" information to pass on.