[quote=Jorick]
Who cares though? It's just a list of which movies you like the most, not which movies are objectively the best ever. I've never seen The Godfather either, for instance.It's a subjective personal list, so it's about what you've already experienced, not the whole of movies that exist. 
[/quote]

It's mainly because every time I watch another movie on that "ohfuckwhyhaveInotseenthisyet" list, it makes it into my top 10 or 20. Making a list feels a little redundant when I'm (sort of) aware that there's a whole bunch of other films out there which I'd prefer to the ones going on that list. If I'd only ever seen ten films, all of them (say) Michael Bay films, would it be worth making the list while being aware that all you've experienced as-of-yet is a thoroughly subpar mockery of the great films that do exist?