At this point, I wouldn't quit over one kid, but I'd probably be more proactive than reactive with a problem child. One of the joys of secondary is often they just go away. In elementary where they have one teacher all day, it's tough to hide that kid or hide from that kid.
Someone lumped everything together and said schools don't discipline kids any more. Let me tell you, teachers try, but we are overruled by administrators who are bullied by parents, advocates, school soliciters as well as the kids. And kids know their rights better than the teachers do.
My son sometimes talks about going back to school to get his teaching certification, and I tell him not to. He sees what I do and he thinks it would be fun, but it's taken me years to develop the rapport and reputation I have with both the kids and their parents. I think I'm fair, but honestly, it would only take one kid, one thoughtless response on my part, and the whole thing could be in jeopardy, and that's in the back of my mind most of the time.
There are tons of things that go on in school that don't get reported, and it's all because administrators don't want the negative publicity. One local school recently was under fire because the number of times the police were called to the school was in the 100's but the number of times reported to the state (a requirement) was 12. Go figure.
Our policy here is if a student misses 20 consecutive days, he is dropped. We have one who misses her 20 days, but because she needs to be enrolled in school or she is breaking her probation, she gets the letter and then re-enrolls. The school gets money and she makes probation and it happens every 20 school days. She'll be 21 in January. I think her kids may already be in the elementary school (just kidding, but it's funny to consider).
And that is just one story....