Hi U
I had a mellow one until 3.5. In the summer before he turned 3.5 he would through tantrums and became stubborn in a way we had not seen before. My DS overall has an awesome demeanor and behavior but around that age also started to express frustrations that his body couldn't do what he wanted. I think for gifties it's how the growth gets expressed because they have expectations for themselves that other kids might not. My DS was terrible at writing we even took him to OT at 4.5 because he was so frustrated and we needed to break the cycle of attitude about it. But 3.5 is way too young for that. I went for calm - talking in a soft voice, I know this is difficult - and if you can see it escalating, before it blows, can you head him off with some suggestions. Oh you want to make a robot, let's do a rectangle for the body. DS at this stage began asking us to draw for him and we did and do, but I think that might have been the wrong move because it made him further frustrated that his stuff didn't look like ours. In retrospect I would have done more sharing, I'll draw this part, you draw this part to make it look more like what he wants but still keep him in the game.
The bright side, after a year of frustration and resistance, between 4.5 and 5.5, he is now much better and much more willing to do it on his own. Although still comes up. Truthfully I am now glad of the issue, it's the only thing he cares about that hasn't come easy, so he has to work. Of course it would have been nice to have that lesson without the fuss!
DeHe