High patient turnovers, I'm an adrenalin junkie so ED is perfect for me as on any given day we can get abusive patients to severed limbs or road accidents to a cut hand. If you are a fast learner, can be an octopus and think fast on your feet while also being able to handle the god complexes of Doctors then that alone makes you ideal.
Patient turnover, variety, challenging, using critical care and basic "this is how you put on a Bandaid" skills the same day, getting trust from coworkers to use my brain, critical thinking, coworkers that understand dark humor, take out meals, not being afraid of codes any more, getting to do/see almost every procedure at least once, knowing I can manage in any specialty if I have to, stupid triage complaints (and YES we do diagnose in triage, even if it's just ruling out everything that can kill you in the next hour).
The best part is admin knowing that for every piece of paper they add to our load the pt turnover slows down, and so does the cash. We push for MINIMAL paperwork, and on occasion we win.
I love the fast pace, not knowing what my day is going to bring, expecting the unexpected, learning a new procedure each time I work, and working with the doctors side by side. I love the dark humor, the frequent flyers, the traumas, the triage chief complaints, and the team work. I love how one person is designated to make coffee at 0300 for the entire ER and how we all flock to the break room after smelling it brewing. I love the bond us ER peeps have!