Teaching challenges

This is my 16th year of teaching. You would think that nothing could rattle me....well, not much does anymore, but two things happened today in one class of 8 students, 11th graders, which reminded me that I need the Lord's patience every moment. First, I closed the door to the classroom after the students had come in. One kid said, "Oh Peter is still outside. He's in the bufe." I shut the door anyway and proceeded to start class. Peter shows up 10 minutes later; "Where were you Peter?" "Oh, I was in the bufe, and I had to stand in a long line, and I was buying things for like 4 other people." I just smiled and let it go. We then proceeded into the lesson, having already reviewed without Peter, and I asked them to take out their notebooks. Peter asks his classmate for paper and a pen......for 2 months now, Peter has not had a notebook or pen for my lesson. Today was the last straw. "Peter, you are, once again, unprepared for this lesson. Goodbye!" He gathered his jacket and left the class, with my warning not to come back to my class without a notebook and pen. We'll see....... So we proceed to talk about character and personality words. "Ok, who can spell the word 'extrovert' for me?" Angela raises her hand, "Extravert". "Actually, it's spelled with an "O" not an "A", Angela." "No, I looked it up in the dictionary and it can be spelled either way." Now I know this is not correct, but with Angela, one simply cannot argue...the past two months have been nothing but a boxing match with her over what is correct in English and what is not.......so I let her continue on in her bliss of thinking we can spell extrovert with an "a", and moved on with the lesson. These two examples show me just how difficult it is to demonstrate the love of a heavenly Father to high school kids.....what is the balance between discipline and correction and grace, all the while allowing His love to flow through instead of my flesh to rage to the surface? Ah, the challenges of teaching..........