Even the most skilled filmmakers sometimes make mistakes. Depending on the movies you like to watch, you’ve probably spotted your fair share of plot holes over the years.Some fans poke fun at perceived plot holes in their favorite flicks, even dedicating entire websites to movie blunders.  It can be entertaining feeling like you’re smarter than the screenwriter, after all.

Sometimes, people are right to lampoon movies for obvious plot holes that they should have caught — after all, we can only ignore so many logical flaws. However, there are some famous plot holes that aren’t actually plot holes at all. They have a logical explanation for why the plot twisted and turned the way that it did.

For this list, we’ll be defining plot hole as an aspect of the story that goes against the logic set forth by the rest of the plot or the movie’s universe. An inconsistency, like someone’s glass of water changing places throughout a scene, won’t count as a plot hole. Neither will character choices — a character not making the obvious choice isn’t a plot hole, it’s characterization.

These might cause some fan wars, but they’re not errors. Here are 16 Movie Plot Holes That Aren’t Actually Plot Holes.

16. Marty’s parents don’t recognize him

Michael J. Fox as Marty McFly in Back to the Future 16 Movie Plot Holes That Arent Actually Plot Holes

In Back to the Future, Doc and Marty accidentally travel back to 1955 without enough plutonium to get them to 1985. While they’re trapped in the fifties, Marty meets his parents as teenagers. Trying to make sure that he’ll still be alive in 1985, Marty orchestrates a moment for his parents at the “Enchantment Under the Sea” school dance before coming back to the present day.

Given how significant Marty became to them in 1955 — saving his father from getting hit by a car, getting hit on by his mother — fans have asked how his parents didn’t recognize him in 1985. Isn’t that a plot hole?

Not necessarily. It’s easy to forget a face after thirty years, especially if it appears in a context you don’t expect. His parents forgetting someone they only knew for a few days is one of the most realistic parts of the movie.

15. Nero is oddly patient

Eric bana as Nero in Star Trek 16 Movie Plot Holes That Arent Actually Plot Holes

In the 2009 Star Trek reboot, a lot of fans had questions about the timeline of events. The movie starts off with Nero’s ship Narada attacking a ship that James Kirk’s parents are on, just before an infant Kirk is born. Then, of course, the movie flashes forward to Kirk as an adult seventeen years later. Two decades go by in the movie’s timeline before Nero becomes a villain again. What gives?

While some people think that it’s a plot hole that Nero is apparently just chilling for years, waiting to take action again, there’s actually a reason for his absence. A deleted scene in the movie reveals that he was actually captured and locked up by Klingons during that interval, giving Kirk plenty of time to grow up and become a leader.

Convenient? Yes. But not a plot hole.