We Found Love may have had lot of chart success, but Single Ladies is WAYYY more Iconic. There was a tv show called "Single Ladies".. And ever since Beyonce started wearing leotards, I notice a lot of other female artist started wearing them during there performance.
When you are imitating the Single Ladies dance without saying anything, people already know what it is.
During Halloween, if you put the leotard on, wear silver gloves, and hump your hair, people will automatically know who you are. You don't have that with We Found Love. Everyone just knows the song and that's it.