When I was 20, I went to teach for Summerbridge (now called Breakthrough, I believe) San Francisco. I was an immature 20; I didn't look for housing on my own, opting instead to do a homestay with the family of a kid in the program. After about two weeks, the head of this household told the program that I needed to leave because I had a negative attitude.
I'm ashamed of how I behaved that summer. I was whiny and dependent, instead of taking responsibility for my living situation. I was also a bad teacher -- impatient, volatile, unmethodical, bad at prioritizing, taking everything too personally. Teaching badly is particularly shameful and horrible because of the power differential and because the harm a bad teacher can do can be so lasting--think of bad teachers you've had. Some teachers may be great at it from the moment they step into the classroom. I learned to be a good teacher from being a bad one, feeling terrible, fixing what I was doing wrong, and then building beyond problem-solving and troubleshooting to include the real work of teaching and learning--spurring each other to greater and more complex understandings, getting more flexible and more precise with what you know and what you can do.
I'm a pretty good teacher now, and I know how to get better at it -- I know what I want to reach for next -- and I learned that partly from being bad at it. Being bad at it was, in that sense, good for me: it was a part of my development.
But it wasn't a part of my students' development, or it was a bitter one, even if the bitterness was fleeting. I think I did some good things with and for them, but I also think I wasted their time, confused them and made them feel bad. I used them in my arc, and I'm not convinced the use was mutual enough. This is one situation in which, rather than being a paralytic or a tourniquet, (my) shame really has acted as a spur for (my) improvement -- it's worth it to me. I love teaching and I love being good at it. But I have trouble saying it's worth it, period, when the way I learned to do it better meant embittering someone else's days and confirming their suspicions of learning.