And people wonder why so many women feel insecure.

Michelle Kirk has been training for the New York City Marathon for quite some time. This past Monday, like most other days, the 28-year-old mom set out on an afternoon run with her daughter around a neighborhood in Davie, Florida. But in the middle of their run, a man interrupted her by stopping his bike in her path-telling her: "Hey, not for nothing, but you need a new sports bra. Your boobs are sagging."

And that's not it: the complete stranger continued to make comments about her breasts, despite the presence of an 18-month-old toddler in a stroller. "He told me if I keep running the muscle fibers are going to break down and my breasts will start sagging even more than they are now," she told the New York Daily News. "He was like 'They're already heading south. I don't think you want that.'"

Kirk says she contemplated going "all New York" on him, but decided that it was better to leave and get as far away from the situation as possible. She later took to Facebook and shared a sassy post expressing all the emotions she felt after being so rudely confronted.

Kirk says she has felt insecure about her breasts for years, which is why when her post received a lot of positive attention, it did wonders for her shattered confidence. "It shouldn't be about who wears what better or looks better," she said. "We gotta stick together and build each other up. We need to see each other for who we really are. We're not perfect."

As for the bully in the park, we can only hope Kirk's viral post got back to him, and remember: if you can't say something nice, don't say anything at all.