Gilbert's two favorite words (after 'train engineer'). He is in that phase of wanting to establish his independence (like school doesn't do that enough for him already!) and control over decision making.
Now when we asking him to do anything his immediate response is, "I don't want to do that," or "I can't do that." The 'can't' drives me bonkers. I loathe that word. Don't even know what it means.
We've learned, though, to ask him to do something by going opposite so he feels as if he's making a decision yet we don't banter back and forth. Kristen still battles with him a bit, but I've mastered the Machiavellian approach to getting him to do what I need/want him to do.
Time for shoes? "Gilbert, please put on your sandals."
"I don't want to put on my sandals."
"Okay, then how about your shoes?"
"Okay." Mission accomplished!
As for the 'can't', that is a bit tricky and we have to work with him to show that yes, indeed, can can do it.
Compound these situations with 2 1/2 year old whining, and ARRGGGH!
This morning I called him out on it. He was whining wanting breakfast and just being a grumper (imagine that; the result of him wanting to wake up at 5:30!). I put him on our bed and told him to stay until he stopped whining. A few minutes later he called down and said, "I'm not whining anymore." And then crawled off. A small victory, but sometimes it is just tiring!