My four year-old daughter doesn't really care for daily body maintenance tasks like brushing her teeth or pooping. I'm with her on the teeth brushing, but the poop issue drives me nuts. She prefers to hold her poop until it's ready to explode out of her.
There was a long while, when she was about 3 years old, when she entirely refused to poop. Her stated reason was that poops were too hard and consequently they hurt (actually I think her exact words were "Owwwwie!"). So, she'd hold it in for about a week and then when she finally did poop, it was a self-fulfilling prophecy. Sure enough, it hurt like the dickens. We spent endless hours trying to convince her that if she pooped more regularly, say once a day, then it wouldn't hurt so damn much. She was steadfast in her belief, however, that more pooping would just mean more "owwwwie". It was tough to convince her otherwise. Her logic was pretty sound. If something hurts, why do it more often?
The end result was that she'd have these periodic, toilet-plugging, epic, oh-my-god-even-daddy-doesn't-poop-that-much poops, about once a week, and the rest of the time, tiny amounts of stool would leak out into her panties. This irritated me to no end. My daughter soon realized that soiled panties resulted in an annoyed or mad father (FYI, this is textbook-quality bad parenting). So, then we had the problem where she'd try to hide the fact that she had soiled her panties. However, due to her young age, deception was a bit beyond her. She'd generally try saying something, out of the blue, like "Daddy! Don't look in my panties!" Her feeble attempts at trickery were so ineffective I almost felt like schooling her in the fine art of deception, but, wisely, I have not yet done so.
I soon realized that I needed to be more supportive and less annoyed if we were ever to make any progress. Of course this is the tactic my wife uses almost all the time, but I'm just not as good at this as she is. So, I've been making a concerted effort to mask my annoyance when she has a little "accident", which, luckily, doesn't happen nearly as often. Now, she merely does a poor job of wiping.
(One of the surprises of parenting was that kids don't just figure out how to wipe their butts. I never thought I'd have to explain to someone how to wipe. Weird. Evolution should have weeded out all the people who didn't wipe their butts well. Who is mating with these folks?)
So, when I help her get ready for bed, and I find soiled panties, or evidence of a poor wipe-job, I do my best to state very-matter-of-factly, "Whoops, looks like there's a little poopy on your bottom. Let's go get you cleaned up, sweetie.". Yesterday, my daughter turned to me and said, "Daddy! You don't sound mad at all!" I explained to her that I've been working on being a better parent and that there was no reason for me to be mad about poop. She replied with, "You're doing a great job, Dad!" and she gave me a big thumbs-up.
Wooo! Two thumbs up for my parenting!