I've only been "fired" from a job once, and even then they told me the news, it was more of them "letting me go" because it was clear both parties were not happy. When they first said, "today is your last day," I thought I was going to faint. I am a planner, I always have a Plan B. They broke up with me before I could meet someone better and end it with them. So I had a good cry, was escorted out by security and drove home (still crying) to an empty house and a full liquor bar.
Before I joined my current job, I had a lot of internships and short-term positions and my last one was awful, almost rivaling the one that I was fired from. I'm not a huge crier but I would cry every day at my old job. It got so bad that my parents would come down to check on me in Chicago to make sure I was still doing things, like showering and going outside because I was so depressed. To quote myself on New Year's Eve of that year, I told my closest friends that if I was still at that job the same time the next year, they had permission to slit my throat with a broken bottle. That part I'm not exaggerating. You can ask them.
When you hate your job, like really hate it, you hate everything. Every weekday is a curse and you lie in bed thinking of reasons why you should go in and not call in sick. I've known a few people who have cried themselves to sleep because they don't want to go to work. Making it through every hour and every day is a challenge and sometimes you wonder if you really will survive.
But fortunately, there is some relief - quitting. I don't recommend doing this unless you have another job to go to or if you house can handle one income for a little bit, so there is my disclaimer. When it does come time to talk to HR and your manager, the best phrase out of your mouth will be, "I'm here to give you my two weeks notice." It might be hard to actually say when the time comes but once you do, the weight begins to lift off your shoulders. The sun shines brighter and birds chirp lovingly for you. When I quit my old job, I went out for lunch and for the first time in almost four months, I smiled like I meant it.
People who know how unhappy you are, they congratulate you and take you out to get drunk and start spending the new raise in salary. And you feel like things will finally get better because they will.
Now you all might think that this is overdramatic and that I'm too "committed" to my job, making it my "life," and to some extent, you're right. But at the age that me and some of my friends are at, we're still putting in our time and having to tolerate things we normally wouldn't want to. The work/life balance bit isn't easy and I'm still trying to figure it out too. But fortunately the people I work with are good about it so I don't mind going above and beyond at times.
I don't plan on quitting my job anytime soon and hopefully they don't want to break up with me either but whenever someone asks me about their job troubles and when you know it's time to quit, I can only tell them my story and say, "you really know when enough is enough. You really can feel it in your heart."