My trakehner will be turning 7 this year and we still have little moments where he tries to tune me out and throw training out the window. Our first show was a great example of him-first class, he went bucking down the long side, spooking at everything, jumping over shadows and ignoring me competely. By the second class, he was all like "meh!" and we ended up with a 2nd place. I have been told though that trakehners are notorious for this and actually tend to be the slowest maturing warmbloods.
My soon to be 4 year old on the other hand, seems to be an absolute stellar little worker bee. He's only been undersaddle now for 2 weeks, but its like nothing seems to faze him. His attention holds, he tries his hardest, he picks things up extremely quickly and seems to realize that the quicker he gives in and does things right, the quicker we pop off his back :P