I think the thing with these hit songs is that they have a part of their lyrics that is very simple that everyone sings along to(even if incorrectly) and general sound of them is also so ordinary and simple that people get used to them fast. If you hear a song thats very different from everything else you ever heard you need time to get used to it but if you hear one of these you can relate it to something you already heard. Thats my two cents i guess.