Man, I tried teaching as an intern (I had a class to myself for most of the time, and a supervisor checking on me every few days) for 2 years. Teaching is not for me. Here's what I learned:

It's imperative that you make a strong impression that you will not be fucked with immediately on your first day. Me, I'm a very laid-back guy and it goes against my very nature to start-off like that, which is why I did not do this my first year. It back-fired completely. However, I had studied very hard to get there, and wasn't about to let this hold me back. I did the best I could, but they just didn't give a shit, and neither did their parents although some of the parents would put in the effort of telling me they would make sure their kid would get his/her act together. It was one of the most depressing years of my life. At that point I almost started hating "kids". I managed to survive the first year, but every fiber in my being was warning me to get out of this mess. I didn't listen, but I had decided to make a better impression the next school-year. I was accepted at another school after summer. I mentally prepared myself to be rough from the get go this time around, but it didn't go as planned. A few of my new students, were actually excitedly standing at my door to meet me. I couldn't help but smile, and warm-up to them, as is my nature and the very reason I thought I wanted to become a teacher in the first place. However, that was once again my down-fall, the rest of the children weren't as excited about meeting me or listening to me. Quickly enough, it turned out exactly as the previous experience; I was getting pelted, insulted (ethnicity and accent) and threatened. One day, as I was teaching them some irregular verbs, two boys were calling each other "faggots" while kicking each other under the table. I actually didn't do anything about this for the first 10 seconds hoping that they would stop by themselves, because at that point in my life I just wanted to het through the day, go home and drink/cry. But they didn't stop, and I snapped, slammed my hands on the desk and yelled something like "You are both faggots now stfu!". The whole room went silent, and I knew I had fucked up. The boy sitting in front of them, turned around to them and said, "The teacher just called you faggots", and the room exploded with such a laughter that even I couldn't hold back a smirk. It was only in that moment that I felt I was in control, and immediately took advantage of that momentum or their attention and finished the row of verbs on the blackboard. The kids were still quiet and doing their assignments until one of the boys I scolded got up and stormed out while cursing at me. I had to report to the principal, who wasn't very happy and told me she would call my supervisor to discuss my future at her school. I told her not to bother, and that I would not be returning Monday. I was allowed to go back to class, where the 2 boys started taunting me telling me that they would beat me up after school. Once again, holding back the tears, I forced through the rest of the day. As I left the school premises, the boys started following me on my way home through the park. I had had enough, and I threw my stuff down and they stopped dead in their tracks. I yelled and challenged them to exchange fisticuffs right there in front of everyone. I could see the insecurity on their faces, and both started taking steps back every time I inched forward. I was livid, but not crazy enough to be the one to start a physical altercation. It was clear they didn't want to fight, but I still wanted them to hurt in some way, "If you faggots aren't going to do anything, I might as well go home". I walked home with the biggest smile on my face. I felt like I was Judd Nelson at the end of the Breakfast Club movie. My fist up in the air after victory. It wasn't victory. As soon as the adrenaline wore off after a few minutes, I collapsed on a bench and started crying. I had lost, and lost bad. That was about a decade ago. And, No, I'm not homo-phobic nor do I condone the use of slurs. I know what I did was wrong, but in the heat of the moment you want to sting your opponent, political correctness went right out the window.

I still live in the same part of the city and will run into some of my old "pupils" every now and then. A few of them will still regularly strike a nice conversation with me. It's quite uplifting to see some of them so mature and respectful. However, I never looked back at teaching. It's just not for me.

For those wondering, this happened in Europe about a decade ago. Both schools I interned at were known to be shitty. It was quite obvious that attendance was mandatory and most of the kids didn't want to be there, which is why they were behaving like that. I used that slur against them because they've been quite vocal about their disdain for homosexuals in the past.

TL;DR: I didn't have what it takes to become a teacher and deal with juvenile assholes, and out of desperation started acting like a juvenile asshole myself.