Star Trek: The Motion Picture/WMG

V'Ger begins to understand emotions, thanks to Spock's Mind Meld.
Spock's mind meld doesn't just give Spock insight into V'Ger - it's inability to understand "this simple feeling" - it gives V'Ger insight into the "carbon-based units infesting U.S.S. Enterprise".

It's been shown in the series during that the Vulcan mind meld, BOTH parties share emotions, thoughts, even memories. Thanks to Spock, V'Ger begins to understand its "lack" in not having emotions. Spock's feeling of disappointment that V'Ger's "pure logic" is not the answer goes into V'Ger and makes it understand that it NEEDS emotions to move beyond its programming of simply gathering data. After Spock's mind meld, it begins to WHY understand it is incomplete.

Proof? It tells Kirk and Co. that it NEEDS the information of why the creator has not responded. If it were simply a logic-based machine, it would not NEED. And the fact that the "Ilia unit" changes its tone at that point to a more pleading one is significant.

STTMP takes place in the 2009 movie timeline, not the original series timeline.
Which explains why the other movies don't reference it, why the uniforms change so drasticly starting with Wrath of Khan, and why in The Voyage Home no one says "What??!!?? Another giant probe is heading straight to Earth??? Awwww com'on!"