Charlotte-Mecklenburg Schools and I officially ended our relationship a year ago. I’ll be honest. After my second child graduated from North Mecklenburg High, I doubted there was much I’d miss about CMS.

For the first time in 14 years, I didn’t have to plan my life around the system’s schedule. I didn’t have to fill out forms. I even slept better, freed from the tyranny of the 7:15 a.m. high school start time.

Then, last month, I remembered what I did miss about Charlotte’s public schools.

My daughter, Emma Foley, was just home and barely unpacked from college when she turned her attention to her old high school. One of North Meck’s teachers, Tom Madre, was retiring after 29 years. Though he wasn’t her teacher anymore, she and a bunch of other North Meck graduates decided he deserved a surprise party.

Mr. Madre teaches math, including the school’s most advanced math classes. Both my son and daughter took him for two years of calculus. He taught them well. He also made them laugh. Students enjoy him so much, in fact, that since 2007, they’ve been documenting his wit, wisdom and personal style on a Facebook fan page.

In one post, he is quoted as denying a student’s request to use a calculator to figure anti-derivatives: “I can teach a chicken at the state fair to peck out anti-derivatives.”

In another, he offers female students some dating advice: “When you go to college, ask the guy who his favorite superhero is. If he answers, don’t go out with him.”

“I don’t need to be mean,” he says in another post. “The material is mean for me. You want me on your side. It’s you and me against the material.”

You begin to get the picture. Mr. Madre: Comedian with TI-89 calculator.

To prepare for the party, Emma and other former students purchased balloons, baked goodies and enlisted the help of Mr. Madre’s colleagues to pull off the surprise. Emma even made an apple pie with a pi sign on it. We go for cheap math jokes in our house.

I won’t get all “To Sir, With Love” schmaltzy here. I can picture Mr. Madre rolling his eyes if I do. Based on what I’ve read on his Facebook fan page, he’s a big eye-roller. I also learned you can gauge the intensity of his lecture by how much his shirt is untucked when the bell rings.

But I have to say that it was about the time the apple pi pie was baking that I began thinking not just about Mr. Madre, but about so many excellent teachers my kids had over their school career – inspiring, dedicated teachers at Cornelius Elementary, Piedmont IB Middle and North Meck.

I’m not saying they were all good. But the majority? Yes.

Thank goodness for my son’s first-grade teacher. She never complained when he spent the entire year writing stories about Pokemon characters. Thank goodness for my daughter’s second-grade teacher, who signed her up for speech therapy so she could learn to say the letter “R.”

Some of my fondest memories are of Piedmont teachers – lots of them – who expended ridiculous amounts of energy so students could perform in “Cats” and “West Side Story,” extravagant musicals that no sane person would attempt with middle-schoolers.

Mr. Madre’s classes never performed musicals. They did, however, sing calculus carols each year before the winter holidays.

On a recent Friday afternoon, about 30 former students, now rising college sophomores, juniors and seniors, gathered in his classroom while he was out. He returned, opened the door, looked at the sea of smiling faces and shut the door.

Some students interpreted this as Madre humor.

Actually, no, he told me a few days ago. It was more of a shock reaction. “I had no idea,” he said. “Completely stupefied.”

Emma took the floor and made a few jokes using Mr. Madre’s own lines, including the one about the chicken pecking anti-derivatives. Then she toasted “all the years you spent putting up with unruly and annoying teenagers and making more students than ever love coming to math class.” Another student recorded the moment for posterity.

I asked Mr. Madre if he got misty when he heard the toast. “I’m not going to say that I did,” he told me. “But I was hoping no one zoomed in on me.”

Why is he retiring? Because time served in a large, urban school system counts as dog years, he said. “That puts me over 200 years old and in need of a long nap.”

Mr. Madre, 58, has told his colleagues not to bother throwing him a retirement party. Current students feted him last week. They made T-shirts that say “Calculating the art of being awesome since 1983.” He has been served his favorite foods, including circus peanuts. And one graduate returned her long-overdue calculus textbook. So, basically, these would be tough parties to top.

I remain grateful for Mr. Madre’s smarts, his humor and his ability to demystify complex concepts. And for good advice like this: “Somewhere rattling around your brain is the ability to do these problems. You just have to access it. And not be afraid.”

Handy words not just for math, but life.

CMS gave my kids a good education. I worry, though, about current students. In a recent story, my colleague Ann Helms wrote that veteran principals and teachers “are retiring and resigning in droves, likely driven by pay freezes, rising job demands and an economy that’s starting to offer more lucrative alternatives.”

Maybe new Superintendent Heath Morrison can stop this talent drain. He has pledged to try to visit every school over the next few months. While he’s there, I hope he’ll ask teachers what he can do to keep them in their jobs.

Because, believe me, it’s the good teachers who make lots of CMS headaches bearable – the red tape, early buses and dinnertime robocalls about a recent restroom trash-can fire or upcoming barbecue fundraiser.

It all balances out. If parents know their kids are learning from teachers like Mr. Madre, they’ll probably give the school system a pass on a lot of the annoying but less important stuff.

Even the robocalls.