These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Critical Research Failure: Invictus was not the speech given by Nelson Mandela to Francois Pienard before the start of the 1995 World Cup. It was a speech by Theodore Roosevelt called The Man in The Arena. Invictus was probably used instead due to Rule of Cool.
it's actually Latin for "Unconquerable" and it's also the name of the poem that kept Mandela going in Prison.
Marty Stu: The portrayal of Nelson Mandela can come off like this, at least as it relates to anything directly related to the plot or to the South African government. Unintentionally lampshaded by one of his bodyguards when he goes jogging.
Special Effect Failure: The film uses news footage of the real Nelson Mandela in the beginning (when he's just been released from prison) and at the end. Morgan Freeman may be the only man who could play him in this generation (in fact, an episode of American Dad! had the joke of Morgan Freeman looking like Nelson Mandela), but there is a noticeable physical difference.
What The Hell, Casting Agency?: 5'10" Matt Damon as 6'3" Springbok captain François Pienaar. Still, his performance was mostly lauded by critics, and he ended up receiving an Academy Award nomination for Best Supporting Actor.