10. How Could The Head Bang Stormtrooper Be A Clone?
One of the most well known background jokes of the whole saga is the clumsy Stormtrooper. When breaking into the observation area R2-D2 and C-3PO are holed up in, one of the Empire's finest soldiers bangs his head on the door. A minor mistake that got left in the final film, later editions have added an audible bump, signifying George Lucas acknowledgement of his mistake.
To really canonise it, Attack Of The Clones contained an identical moment with Jango Fett. As Episode II introduced what would eventually become Stormtroopers as clones of Fett, the implication is that the head bumping is somehow genetic.
Aside from that making no scientific sense and the soldier not having a New Zealand accent (like all the clones and Boba Fett have for some reason), it doesn't add up in the timeline. For a clone to be still functioning as a Stromtrooper in ANH is would need to be a minimum of twenty years old, which with accelerated ageing would make it at least the grand old age of forty. I somehow doubt regular soldiers at the major Imperial base would be so aged and likely inefficient, making the whole in-joke nonsensical.