AAA,
EV was more difficult and less so now, but still is. Her more difficult part was as u said, beyond reasoning, and actually beyond comprehension to the adults. She would cry and we don't know what reasons, and she can't be calmed down. ie, even if we give in to her, carry her, she still continues crying. And cry till vomit etc.. that was then (about 6 months ago).
Now, she stopped that cry-and-can't-be-pacified-thing (luckily!). But she is still difficult. Like she will insist she wants to get up the car first. If EJ got up the car first, she will scream and yell and make a fuss. I tried to forcefully carry her in, she will wriggle and struggle.. the last time when this happened, I actually burst into tears cos I was terribly sick that day. I really didn't have the physical and mental strength to fight her. So I got EJ to come down (he was already buckled in his seat), and then let EV go up the car 'first'.. then EJ go up the car again. It can be that terrible.
And this thing repeats in other ways.. like she must be the one who get into the house first, get into lift first, press the lift button first, wash hands first etc.. but the strange thing is, she is not like this all the time. ie. on some days, if EJ got in first, she is totally nonchalent. So all these adds to her being "difficult" because we seriously do not know when she will "explode" into one of her tantrums. But I do think she is slowly slowly slowly outgrowing this.. as this kind of explosion gets lesser.