This type of question always makes me sad.
I am the sibling of one of the children judged by the school-system. I am a year older than my brother and I saw the school issues first-hand. My brother could not get a fair chance at anything. And, quite literally was bullied by his teachers.
Please don't assume the teachers are right, fair or honest.
My little brother was a brilliant, humorous child who, had an IQ higher than that of his teachers. Suffice to say, they had little to offer him that he couldn't get reading a book on his own.
These are the students that teachers should go the extra mile to provide a learning environment tailored to the student. Seems it's easier to write these children off as having ADD or AHDD and give them pills. I assume this by all the prescriptions given for this popular, highly over-diagnosed condition. If our school systems weren't filled with inept educators, we would be harvesting these brilliant minds by allowing and encouraging them to grow at their own speed.
My answer...
talk to your child like you would like to be talked to. Allow your child to be listened to. If there is mention of a particular teacher upsetting them, check it out. Some of our country's brightest students fall between the cracks because of this.
Always be on your child's side; you may have given birth to the person who, will grow-up to eliminate Global Warming, find a cure for cancer or be president of our country. Keep the faith!