Arthur Quiller-Couch, a British journalist, critic, and novelist once said,“Murder your darlings.” While this quote was aimed at aspiring writers, I believe that it is equally relevant to designers.
Essentially, the elements of your design that you really love cause you to have what I call “design blindness.” You loose the ability to be objective about your work. You loose the ability to critique honestly and without bias. This often means they may not be quite as “perfect” as you think they are.
via 52 Weeks of UX – Kill Your Darlings. Seen the results of not getting over personal attachment to a design it’s not healthy for the design.