How can Reese possibly be John Connors father? Can plot holes ruin a movie for you or can you get past it?

Nah. One of my favorite horror movies is High Tension, or Haute Tension, and it has a notoriously bad plot hole. You can even search it, it will come up as “worst plot hole ever.” But I just watch past it. I’m a huge fan of b-movies, I love plenty of films of total incompetence.