The best are people who lie to the doctor. Unless you're hoping to defraud someone (get meds, insurance, whatever) it's not only pointless, it's so counterproductive.

"I haven't pooped in a week." "Hmm, how many servings of roughage do you eat per day?" "All of them. I eat ten apples for breakfast, lunch, and dinner, and I eat the solids left in the juicer after making my all-organic smoothies." "OK, I guess we'll have to do a DRE. Do you mind if my interns help?"

"How often do you floss." "Ten times a day." "That's curious, because your gums started bleeding like a Tarantino movie when my hygienist waved the box of floss in your general direction."

I learned the hard way when I faked appendicitis and ended up in surgery when I was 12. :-)