"Normally I wear flip-flops. All I wear is flip-flops," said Harris.
For decades, podiatrists have been sounding the alarm about flip-flops: they are not stable, they don't provide arch support, they don't protect your toes and they don't absorb shock which can be hard on your legs, hips and back.
"Being in flip-flops is like being barefoot. There is no support," said Harris.
But for the first time, new research has something good to say about flip-flops. And podiatrists just don't get it.
"Why would something that doesn't give you support and cushioning be good for the knees?" said Huntington Hospital podiatrist Dr. Joseph Ferrante.
Rush University researchers followed 31 people with osteoarthritis of the knees. They studied their gates as they wore clogs, stability shoes, clogs and even in their bare feet. They found people who wore the flip-flops had the least pressure on their knees.
Dr. Ferrante says this finding goes against everything he knows about foot mechanics.
"It allows more motion in the foot. It allows more motion on the tibia which is translated right up to the knee," said Dr. Ferrante. "If you're walking barefoot on a hard surface and you do that for a prolonged period of time you would think that would be more painful for the knee."
"I have seen people running a marathon barefoot," said said Harris.
But foot experts believe future research will change what is being said today. They say that thong slippers should only be worn for short periods of time.
"Just wear it when you don't have a lot of walking to do," said Dr. Ferrante.
Flip-flops shouldn't be seen as the cure all for any knee problems. If you have serious knee pain you should see a doctor who might be able to prescribe anti-inflammatories or physical rehab. But flip-flops may provide a little short term relief.