Let's all just agree... Shelly Long's character is THE VILLAIN of this movie!
The whole idea of transforming Gus into Lobo only comes after Shelly is upset that Gertz is not interested in Gus.
Gertz tells Shelly she is not into Gus and kind of involved with someone. But Shelly will not accept that and gets angry with Gertz, even saying, " right, you'd have fallen for Gus like a ton of bricks if he'd been devastatingly handsome and treated you like shit." Gertz denies this, but to add further proof why Shelly is the VILLAIN... in the next scene, all you hear is Shelly essentially saying how it's bullshit when people are saying looks aren't important.
Do I think Shelly cares that Gus eventually finds love? Yes, but when Shelly feels denied by Gertz's honesty... all Shelly cares about is making Gertz eat her words and USES her brother as a toy in her game of deception!
Prove me wrong!
(ps... i love all of you)