It started out so simple.
"Dad, can I go on the swing now?"
"No, your superior brother is using it."
It grew larger with time…
"Dad, can I go training with you?"
"No, I am training your genius superior brother."
Itachi did make an effort to make him feel better…
"You don't suck that much…"
But poor little, stupidly cute Sasuke had already developed a MAJOR inferiority complex.
He found himself struggling with simple tasks…
"Do I deserve this sandwich?"
It developed into-
"This sandwich is too good for me!"
"I don't deserve to look at this sandwich!"
His mother tried to help...
"Your father loves you more!"
Alas, it was a lie.
And anyway, Sasuke was far too damaged to be undamaged.
Hell, this was before his brother killed his entire family. He never stood a chance.