Lets be honest: they are bad EMTs, bad paramedics, on both the ambulances and the fire trucks. Poor clinical providers, poor interpersonal skills, and massive (undeserved) egos all around.
I will also openly say that before I moved to NC, I didn't trust the majority of EMS providers who ride fire trucks, unless I knew first hand that they had worked in a busy 911 systems on an ambulance previously. I still wouldn't trust many fire engine riding EMS providers to treat me (and yes, this includes several of my coworkers), but I will acknowledge that there are a few very competent EMS providers, even though they don't ride the ambulance regularly.
OK, that all being said:
You're a newbie medic, with minimal experience.... Who are you to discount these fire based providers experiences? Maybe they have seen more than you, and know the difference between a good paramedic and a bad paramedic, because they have been doing it long enough?
I don't know anything about your system, but if all the fire crews do is carry your bags, take vitals for you and open doors, than I think that's a waste of a fire crew. a "first responder" who shows up after ALS is a waste of a "first responder" because they aren't "first." But if that's how your system is set up, so be it.
We all make mistakes. The important thing is that you learned from your mistakes, and don't repeat them. This includes flying out the fake stemi and calling a trauma alert or going to a trauma center with a questionable trauma. don't worry about it, and if you make a mistake, learn how not to make it in the future.
As a fire-based first responder, I know what my job is, and I know what the ambulance people's job is. Do I know all the details, all their protocols, and all their procedures? not really. but if my paramedic crew regularly showed up without their bags or other equipment, without their stretcher or carrying device, and expected me to get all that stuff for them, then I wouldn't have a very high view of them. But I do know that my job is to treat the patient to the best of my ability, get information for the ambulance crew, and when they arrive, give a report and let them do their job, as well as stick around helping out until they tell me they no longer need my crew. Oh, and I also have to make sure the patient is as comfortable with the ambulance crew treating them as they are with me (that transferring of the provider/patient relationship is a lot more important than people realize).
When I was first on the ambulance down here, I was told I should have been thanking the FD for coming out to calls. Being a yankee, this was a foreign concept to me, as I always pictured it as them doing their job. different cultures I guess, but I don't expect to be thanked (other than the basic here is my report to you, thanks for the info). But that's just me.
Another thing: you are too new to be bitter, especially if you are bitter because of what you have heard from others. you're a newbie medic; just because they aren't paramedics doesn't mean they don't know what a paramedic is supposed to do (and based on your initial post, you seem to think just because they aren't paramedics they don't know anything, because they are just BLS). I knew some very questionable paramedics when I was just an EMT, especially ones who had less EMS experience than I did.
Sometimes, my delivery isn't the most tactful (as I'm sure many on here will attest to), but I'm working on it. Sometimes I've made the error of assuming someone is being rude or disrespectful, when that wasn't their intent. One time I can remember (back when I was on the BLS ambulance) I had a paramedic fly car assist us, and the paramedic's first words to me were "why are we here?" Suffice it to say, I took offense to that, and after we transported the patient, we had a chat about it. Her intent was not to imply that she didn't want to be there but wanted to know what was going on with the patient, and my response back to her had been perfect. Again, minor communication issues.
Act confidently (you are the highest training medical provider), but if you treat the FD like stretcher fetchers, and bag carriers, they aren't going to have a high opinion of you. But if you do have an issue with a FD crew, after the call is over, have a chat with the Lt or Captain about it. See what was going on, because your new, so maybe you missed something, or did something that they didn't agree with. Or maybe you were unintentionally disrespectful, and didn't thank them for their service (who knows). But don't look down on the FD just because they aren't all knowing paramedics like you are.