Sounds like you have the wrong job, not the wrong career.
I work in the ED in a rural location (though I live in the the city) --- and the patients are generally appreciative. Throughout the day I get several genuine "thank yous" because in reality, for the majority of the people I see, the ER is all they have (poor, no insurance, etc). I agree it can be frustrating that I cant completely fix their problem (since these people have no other access to healthcare), but I do the most I can from an ED stand point and often times I do more than is indicated if I know they can't follow up.
If they think they have an STD because their partner had a + chlamydia test, swab the, give them some Rocephin+ Zithromax and send them on their way. Its a super quick visit, and I chart them out without 10 minutes. Ear pain in the middle of the night? Give them some Auralgan drops in the Ed for the acute pain - at least they leave feeling better. For the people with the chronic abdominal pain I often have to sit down with them and explain that I'm literally doing the most that I can. I cant CT them for the 20th time because it wont solve the problem and will only expose them to more radiation. "Hey, you need either an EGD and Colonoscopy but unfortunately I cant do that from here, only the GI specialist has the equipment to do that. Judging from your symptoms your upper abdominal pain might be from your stomach producing too much acid, I'll try you on prilosec and carafate ...blah blah blah" Often times they will understand if someone takes the time to explain. there will always be the ones that don't get it and will leave mad regardless, but don't let them get to you.
I work with great supervising physicians and I think that is vital. I remember dealing with some pretty nasty docs during school in clinicals and I cant imagine doing that day in and day out. Overall my docs have been excellent teachers and are easy going/easy to work with. There are some that have their "quirks" and it took some adjusting, but I was able to come to a mutually effective relationship. On slow nights I really enjoy chatting and goofing off with my colleagues - I work with a great group of people. I think that plays a huge part in my job satisfaction
My group also is very productivity focused. Its hard finding a balance between pushing yourself to see more and burning yourself out. Generally if I see 2-2.5 per hour I'm comfy. Anything more than that, I leave work feeling super pooped. There are days when the ED is super busy and I have to step up and see tons of people - but I dont do that on a regular basis for my own sanity.
I hope you are able to find a position you like - with the right patient population and the right colleagues (attendings).