Exasperated and impatient: the same as always . . .

So, I've been trying to figure out if The B has changed much since he started school . . . .
There is, I suppose, the obvious developmental stuff: he can read and write; his mathematics skills have improved; his drawings are starting to resemble actual things and, in social terms, he is beginning to make great strides.
In other aspects, he seems to be much the same as always, although I have begun to notice that certain things are creeping in.
Sighing, for instance, seems to have become de rigueur around here. I'm reluctant to use the word 'attitude', but at times there is a certain edge that I don't remember from the pre-school period.
Earlier today, for instance, he asked me to construct a complicated paper aeroplane. I obliged, as always, although, to his obvious exasperation, I proved unable to complete the prescribed task in the timeframe that, unbeknownst to me, he had allotted.
'Hurry up,' he muttered wearily, before sighing a great sigh. It isn't an isolated episode.
Later on, for example, I noticed he had started drawing a picture and so, keen to take an interest, I enquired about the subject matter.
Once again, he emitted the exaggerated sigh. 'Just wait and see,' he murmured under his breath, his annoyance at the perceived intrusion quite clear.
I thought for a time that he had picked up such impertinence from school. But The G, her own bossiness knowing no bounds, has, if anything, been even more impatient this afternoon, demonstrating that, when it comes to huffing and puffing, her brother doesn't hold the exclusive rights.
So for now, the answer is no, I don't think The B has changed since he started school. 
The truth is, I reckon he has always been like this . . .