I've noticed that the folks who go into this with stars in their eyes tend to burn out the most often. This isn't any fault of theirs, just that this field isn't accurately represented by the media or even by nursing professors, who tend to be long out of touch with the realities of this job. And there's really no way of explaining what the job is like or what emotions are involved until you're there doing it yourself.
Personally, I'm of the opinion that feeling "passionate" about taking care of sick people isn't enough to get you through your first few years on the floor. You really need to be a workhorse for the most part. You need a very very strong work ethic. You have to know when and how to let go of the things that are out of your control. You need to have the emotional hide of an elephant, not just for dealing with the soul-crushingly sad cases (elder/child abuse, cancer, the struggles of the poor, etc) but also the supremely frustrating days that consist of nothing but incontinence, bed jumpers, drug seekers, overbearing/enabling/manipulative families, violent alcoholics going through withdrawals, mean doctors (sometimes not their fault, their job is a whole 'nother realm of stress), and just a metric fuckton of sheer and utter rudeness in all directions. People screaming and swearing at you because it's somehow your fault that they ended up with a broken back because they decided that getting drunk and high and jumping off cliffs was a good idea. People with unrealistic expectations of medical science. People who think it's your fault that the pain medicine isn't working but they've been recreationally snorting oxycodone for years. And throw on top of all of that the staffing issues and impossible demands management makes despite not giving you enough techs to help.
Let's not forget the physical toll that this job can have on your health. Your knees will creak and pop by the time you're 30, your back will hurt from turning obese people. Waking up stiff and sore.Holding in pee for hours. Eating in between charting. Fucking up your circadian rhythm from working night shift.
Oh, did I mention that if during the chaos that if you forget to document something that you could get your license suspended if some lawsuit-happy bastard decides to sue?
It's also very easy to become disillusioned when you realize that JAHCO loves to ride everyone's ass about "patient safety" but no one wants to address staffing ratio because in the end everything boils down to the almighty dollar.
That said, do I like my job? Generally, yes, but I didn't go into this with stars in my eyes. I have passions in life for my various hobbies but I will admit that I don't actually have any "passion" for my job. It's just a job for me, and I was raised to give 110% to earn my daily bread but not to expect it to make me happy. Maybe that's just because I'm Asian and that's how we tend to roll, I dunno. I have other outlets for passion in my life, and that itself makes me happy with where I am and what I do. I never expected my job to make me happy, and I feel more well rounded this way. I love my patients even when they don't like me back, I will bend over backwards for them even when they're being rude and obnoxious, but their happiness isn't tied to my own.
Does the paycheck make me happy though? Heck yes. I love that I sacked away $25k in the bank within the first year of work and can afford to take awesome vacations with my SO (also an RN) and not have to worry about pinching pennies. I love that I can work 3 days a week with the option of picking up more shifts with fat bonuses in between. I love that when I clock out I don't have to think about my job anymore until the next shift. And even though it's stressful, I love to learn and I like how this job keeps my mind sharp.