Terminator 2 (1991)

First, I am one of the only people who didn't like Terminator 2, which reeked of sequel cliches.  The film was really just an attempt to out do the scenes and catchphrase "Hasta la vista, baby." from the original film.  So, it had a lot of spectacular stunts, but the whole concept was flawed because the new terminator.  The actions of that terminator were just made to take advantage of the new computer effect of morphing, which was a new capability at the time.  It wouldn't have been logical for the the T-1000 to continually take the shape of a human, which would not necessarily be best suited for the task of killing John Connor, nor does it make any sense that it would make sense to revert back to the the same human it was in the beginning of the film, as that cover was blown. 

One of the problems with ANY robot is that there is NO reason for the designer to put vital controling components in the head of the unit.  This means that shooting it in the head would have any signifcant effect to stop or slow down the terminator.  Yet, this terminator which doesn't have any vital components in it's head, is repeatedly shot in the head.

Another problem is that while after repeatedly shooting the T-1000, it was obvious that the T-1000 was not being damaged by those shots, so that every time it was shot in the film was a waste.  Such shots were just added to look cool, and look damaging.  This is just like any other movie or cartoon battle where the fighters never take significant damage until it's time for the conclusion of the fight.

But the most problematic was that it was some type of reunitable liquid metal.  There is no reasonable theory as to what would control the metal to command it to return to the larger grouping of metal (theT-1000).