There's alot of reasons why people prefer 1D than others, for example they are fun.
Alot of artist say that One Direction isn't that kind of band that are bad persons, even in cameras are themselves. Being themselves is a reasons why girls love this guys!
One Direction have that lyrics that al we want to listen to. In my opinion the song "Little Things" is for girls that doesn't love themselves. Other song is "Diana" that in my opinion is for girls that are suicide. I love that songs!