A severely unhealthy co-worker took up CrossFit a few months ago. Now he thinks he's a fitness expert. He's always asking co-workers how much they lift, giving people advice. He told me I could squat more if I improved my form—even though he's never seen me squat. He did the 22-day push-up challenge and quit after three days of assisted, half-push-ups.

He was complaining about sore knees and said he thought it was from his squatting (which is at less than half his body weight). I asked him how he's squatting and he demonstrated the weirdest squat technique I've ever seen. It included him keeping his feet straight, then twisting his knees outward on the downward movement, then twisting them inward as he comes up. I stressed the importance of proper form to prevent injury—and suggested that's why he was having knee issues. He looked at me like I shouldn't be correcting his fitness expertise. I shared a couple of squat form videos with him. He never said a peep about them.

A few weeks later, he was off work because his knee pain had gotten so bad and his joints were inflamed. When he returned to work, he mentioned that he built his own CrossFit box in his basement. His knees are in such rough shape that he can't bend one back 45 degrees without pain. He also mentioned that Costco had a sale on bacon so he bought ten pounds of it.

He's built like Chris Farley and is one of the judges in a CrossFit competition next month.