We all know that Oro is pretty much OBSESSED with Sharingan......
Itachi fought Oro once and ADDED Oro to his pawn collection(He added another event to his plan)
Itachi beat the crap outta Oro and Used that opportunity to SHOW HIM THE TEROR OF SHARINGAN
Itachi traumatized Orochimaru in a very dramatic way that him so darn interested in sharingan....:itachi is
It also explains why itachi went easy on sasuke(Sasuke vs itachi fight)...
After using Orochimaru to get to sasuke, He decide's Throw him away like a piece of TRASH LOL
JUST TO LET Y'ALL KNOW(I AM NO OROCHIMARU HATER)....Itachi is cool but not the GREATEST
Everybody's got their opinion, i dont hate on other's LOL :D