I completly agree with was said above, and only want to add one thing: You can use the wide angle for shots that break the "normal" rules. The view ist just strange for most pictures and you can use this as an advantage to do things out of the ordinary.
Most ultra wide lenses have quite a bit of distortion, use this to make shots the viewer finds some kind of awkward (but don't overdo ist
)
Some examples from myself:
Bild: Dreistes Model | VIEW Fotocommunity
Bild: Wer hat Angst... | VIEW Fotocommunity
And a link to someone who really spezialized in this kind of things (and is truly a master as I think):
Fotos von Sebastian Niehoff - Fotografin aus Wanne-Eickel - fotocommunity.de