Michelle Icard was at a North Carolina Starbucks when she overheard a group of teenage girls saying mean things about one of their classmates.

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Icard was so appalled by their speech that she decided to leave them a note asking them to be more kind in the future. She also bought them more coffee.

"They were talking loudly, so I could hear every word,” Icard, a blogger, said. “I was crawling out of my skin. I was physically bothered by it and I kept thinking, 'This is going to stop, one of them will say something to redeem themselves,' and it never happened. They were verbally bashing another girl over popularity issues.”

After leaving the Charlotte, North Carolina, coffee shop, Icard said she couldn't shake the interaction and posted about it on Facebook. "I was shocked at the response I got from moms; it really resonated with them, and one said, 'Order them another round and write a note,'" she said.

"I left and went to do my grocery shopping, conflicted the whole time, and I could see the girls still sitting in Starbucks as I drove home," Icard wrote in a follow-up post on Facebook. "I ran into my house, grabbed a note card and wrote a quick, heartfelt note. Then I ordered three mini frappuccinos on my mobile app and headed back up to Starbucks. They were still there. I walked up to them and said, 'Hi, girls. You don't know me but it looks like you're here studying, and I wrote you a note of encouragement.' I handed them the card and walked away."

In the handwritten note, Icard told the girls that they are “obviously pretty and hardworking,” but she wishes that their “kindness matched their pretty exteriors.”

"You three are obviously pretty and hard-working," Icard wrote. "I wish your kindness matched your pretty exteriors. I heard you talk about a girl who sang a song about being lonely in the talent show -- and you laughed. About a girl who couldn't be lead singer because you got all the votes, about crappy presents other people have given you and you sounded so mean and petty. You are smart and you are pretty. It would take nothing from you to also be kind."

“The nice thing was, I had a lot of moms say, 'I read this to my daughter. It's important for them to know your words have an impact,'" Icard later said.