Reasons to not achieve

"Low ability" students have always been a bit of an enigma to me.  I put them in quotes, as many times they are not actually low ability, they only demonstrate low ability under assessment conditions.  They come in many shapes and sizes.

The student that does not value education.
On occasion I get one of these.  They're the ones that ask why are we doing (whatever it is)...   The answer is fairly simple in that the curriculum is set and the government pays me to teach it.  Blame your parents they elected the government.  The alternative is to identify how each topic is applicable to the workforce (which inevitably ends in I'm not doing that) which makes embedding context for these students a reasonably ineffective approach.  I have a book that does this, if they continue I direct them to it.  Eventually we get to the point where they accept that education is an enabler of general occupations and that their chosen occupation (footballer, dancer, stripper) may not be their only occupation and that math skills will help them in their future life.

The student that sees work as a favour that deserves special credit any time they do it.
"But I did work" - So what? Still less than everyone else and well below your level of ability.  Doing more work in my class than anyone else's is not an excuse for poor behaviour.  If a student disrupts ten other students but finishes their work, it still is not acceptable.  Maturity is the only thing that reliably fixes this, as they get a goal that they need your subject for.

The student that cannot perform under assessment conditions.
I don't have an answer to this one.  I've had to use teacher judgement on a few of these over the years.  They sit in class and work.  They complete assignment work.  If it's done 1-1 they're fine.  Put the word test on the top and their brain explodes.

The student that sees you as an equal.
I'm not a friend, I'm not a colleague, nor am I an acquaintance.  Students don't have a right to discover whether they should respect you or not.  When I walk into a class, I set the rules.  By rights of a degree and being placed in the role by the school I have earned the respect given.  I decide when these rules are broken.  I may tighten the rules at the request of a class.  The right to negotiate is born through acceptable behaviour, not through misbehaviour.  If I don't do a good job teaching I will lose that respect over the year, but I deserve the benefit of the doubt in the early days.  This is best fixed with a team leader or deputy present.  Explain the problem, probably no-one else has.  You will now become a lone entity in the world they don't treat like everyone else and may help them keep their first job.

The student that avoids work.
This student needs to see the counsellor, toilet, drink fountain, office, nurse, dentist at least once per day.  They are late to class and have not been told that assignments/tests/homework are due.  They are probably the easiest to fix.  Fail them.  Early.  Sit them down and explain to them why they are failing.  Give them catch up time at lunchtimes and additional homework delivered to parents.  Then encourage them as their grades improve.  Don't stop too early, it may take a few years to change a habit of six or seven.  It takes a fair bit of effort.

The student that believes life is fair.
Guess what.. it's not.  If I believe you need more attention than another student to succeed, I'll give it to you.  If I believe that one student will respond to a stern word, and another will not, I won't bother with the latter - I'll try something else.

which leads to...

You're picking on me because I'm .....
It's true, some students I will give a hard time to, because I think they'll come good and make something of themselves.  Others require different strategies and a host of people and money for special programmes before they come good.  Swearing is a favourite - kids from good homes don't need to get the habit, others from difficult home lives need tolerance as it takes time to come around.  "Unconscious" swearing is one thing, being sworn at it another.  Very few homes allow disrespect to parents (it's fewer than many believe), and this respect has to be transferred to teachers and being sworn at crosses the line.  I love the shocked look on their faces when I say my grandfather is darker than them and that they need to consider their words carefully because, like them, I take racial vilification comments very seriously.

The student that tries and fails, every time.
If a student can't pass your course legitimately, then you need to act.  Create a course for them, move them, do something.  It's soul destroying to you and the student to allow this to continue.  Heterogenous setups are a trap for this sort of thing.  One curriculum does not fit all unless you are a highly (and I mean highly) organised and skilled operator.  I have not met that many that do this well.