Originally Posted by Moonwing
Its a common trope. Earth in si-fi is a planet with primitive life and in cosmic scale is unimportant BUT at the same time it is the one that becomes the most important thing in the universe because its inhabitants, no matter how primitive they are, will save that universe in the end. And human protagonist will get to bang the most beautiful alien girl because he is soooo special (yep the same as Thor/Jane but in reverse). Its human arrogance - we are the best in universe and our planet is most important -the end. I may hate it with passion - but like you said - most audience need this trope to relate.
Well maybe GotG will make you feel better, yes?