When William willingly agreed to go potty at Target yesterday, I made sure I was effusive in my praise of him afterward. You have to encourage these things, and I wasn't going to let him think that it wasn't a Big Deal.
After I'd heaped praise upon him for awhile, I added, "See, wasn't it easy?"
"Yes," William responded. Then after a beat, he added, "But it's not easy being green."