"Strange Case of Dr. Jekyll and Mr. Hyde" subversion with Quark/Lumba (Quark's female persona from "Profit and Lace")---and Lumba only being abhorrent from the POV of Ferengi male society.
So it starts as a weekend thing. Bashir does the surgery both ways, on request, every weekend, no questions asked. Quark tells himself it's just "exploring" at first, no biggie. But the truth his, Quark is happier as Lumba. "Quark" is a traditional Ferengi right down to the core, but there's always that pressure to suppress the other self...which is not so much an other self as...well
Lumba is a people person. She's fun, she dresses in pretty clothes, she gets attention. The Dabo girls like her a lot and she likes hanging out with them too. You could say she's not afraid to admit she likes root beer.
Rom thinks it's a big mystery at first--does his brother have a secret lady friend-business partner who's also a lot nicer and happier than him? But as soon as he catches on, he's immediately supportive, and ultimately helps "his brother" fake die (in dramatic fashion). Lumba lives her life 24/7.