I'm a few weeks into the "substitute teacher" experience now, and I have to tell you, it has been an education. (Yes, that's cheesy, but also accurate!) Here's a sampling of what I've learned so far.
Teachers do not get paid enough. They just don't. There may be some districts out there that are able and willing to adequately compensate their teachers, but I am willing to bet they're mighty few. My circle of family and friends holds quite a few teachers, and I've always had a lot of respect for the profession and all it requires, but mercy....these people work their backsides off.
Being a substitute is really nothing like being an actual, full-time teacher. At the end of the day, I walk away. I don't have papers to grade, parents to contact, materials to track down (and frequently purchase out of my own pocket), classes to take, nothing. I don't know how teachers do all that they do and remain sane. You have to really, really care about your students to be a good teacher, and I've seen lots of people who really, really do.
That being said, subbing is still kind of stressful. If you've ever cooked in someone else's kitchen, you know the feeling of everything being in a different place. It's confusing, and it slows you down because you don't know where all the tools are. That's how I feel sometimes when I go into a classroom. I understand the goal, but how to get there isn't always immediately clear. Thankfully it seems like most teachers leave good lesson plans, and so far all the other teachers and staff have been incredibly helpful and kind.
Just as I thought before I started, I've had mostly good days, a couple really good days, and one absolutely horrible day. Let's just say that if I didn't already have kids, that assignment might have done double duty as long-term birth control. It was bad. But I survived (and so did the kids), and I've learned to be a bit pickier about the age groups I accept. :-/ I've also learned to always have something to eat in my purse, and that water bottles will leak even if they say they won't. Comfortable shoes are a necessity. And I need to start hoarding pens.
So overall, I'm doing okay. I have no desire to go back and get a teaching degree, but being in a classroom two or three days a week is working out pretty well. I learn a little more with each assignment, and I'm meeting some really nice people too. Going back to work hasn't been quite as scary/awful/depressing as I feared, thankfully!