Scott McClelland had planned to share his marketing insights to 200 business students at the University of Houston, but by the time he finished the hourlong lecture, he'd thrown one student out, started a Twitter feud with another and provided a life lesson for all.

Many Houstonians would recognize McClelland as the smiling, bespectacled pitchman who appears with Astros Hall of Famer Craig Biggio in H-E-B television commercials. His day job is president of the grocery chain's Houston region.

"People notice little stuff. In many of our locations, there is a Wal-Mart or a Kroger right across the street from an H-E-B, and often there's a fine line of distinction in the customers' mind about what gets them to turn in to our parking lot," McClelland told me. "You seek to differentiate yourself from others, and it's little things that make a difference."

About 20 minutes into his talk, he spotted one student leaning back in his chair, sound asleep and "sawing logs."

"I asked the student sitting behind the sleeping student to tap him on the shoulder. When he sat up, I told him that he looked tired and he needed to leave. He just sat there, so I told him again that he needed to go," McClelland recalled. "The whole class looked on (as the student left). I think they were surprised someone would actually address what probably is tolerated in other classes they attend."

McClelland said he didn't plan on doing anything that dramatic, but in that moment he saw a teaching opportunity.

"When you are at work, or school, you need to bring your 'A' game, because people are always watching," he said. "A year from now, the students in the class won't remember the slide that I showed them on how we partnered with Whataburger to develop a retail package for ketchup, but they will remember that a kid fell asleep in class and the H-E-B guy didn't tolerate it."

McClelland said doing nothing would have made him guilty of "the insidious acceptance of the B grade."

"It's easy to walk by little things that aren't a big deal - like someone sleeping in a class of 200," he said. "However, doing that detracts from excellence and lowers your expectations about what you're willing to tolerate on a daily basis."

Life's most important lesson is that actions have consequences, and sometimes we learn those things in embarrassing ways.

One student, though, disagreed and anonymously took to this generation's soap box: Twitter.

"@HEBScott of @HEB overstepped his authority and publicly humiliated a student at @UHouston during his guest presentation by kicking him out," the person who adopted the handle @UHStudent1 wrote. "It was not his place, nor his right, to discipline and humiliate a student."

Apparently UHStudent1 doesn't know how disruptive a sleeping student is to a lecturer. But because Twitter is public, and millions of people can watch the conversation, public figures and businesses know they must respond to critical tweets.

"You go to UH to learn how to succeed post graduation. Sleeping in class won't get you there. Lacks basic courtesy," McClelland responded. "In the business world, which student is training to enter, you don't sleep during meetings."

Other students came to McClelland's defense, and Chronicle sports columnist Jerome Solomon alerted me to the debate. I asked if @UHStudent1 would identify himself or herself and explain what happened.

"I have to protect myself, as you well know from your position," UHStudent1 responded. "I was horrified by what I saw transpire."

In my position I've reported from war zones in Africa and the Middle East. I've interviewed aid workers and human rights activists about real atrocities when revealing their identities would get them killed. I asked UHStudent1 to dial back the drama and got no response.

Which is the second life lesson: Keep things in perspective.

Despite criticism from other students, UHStudent1 hectored McClelland for two days before he provided an email address to take the conversation private.

Professor Amy Vandaveer wasn't in class that day, but she doesn't think McClelland was out of line. While many UH students are the first in their families to attend college and often work multiple jobs, the importance of courtesy and professionalism is part of the curriculum.

And she has good news for anyone worried about those young whipper-snappers.

"The majority of my students were embarrassed that he had to stop the lecture and kick someone out," Vandaveer said.

UHStudent1, however, remains defiant, she said.

The most powerful classroom experiences take place when lectures transcend into life lessons. Guest speakers with real experience offer those opportunities, and students shouldn't diminish them by creating a distraction, either by sleeping or acting out.

Let's hope most of the students learned something from McClelland that day that will prepare them for the workplace.