The Storyteller said:
That episode was indeed awesome, it could've worked as a series finale, acutally it would've worked better than the current one (even though I loved it) because they kind of ignored the ending in the movies, when Fry finally won over Leela. :/
Actually tonally I think it's pretty obvious what happened. I can't believe I'm about to write this.
She's known that he likes her since the beginning. The bee episode is the moment she realized that yes, she did have feelings for Fry. They follow that up with Fry successfully asking Leela on a date in Farnsworth Parabox (she flips the coin and then decides that, no, she really does want to go on a date with him). Devil's Hands is the moment that she allows herself to actually give into her feelings properly because she realizes that Fry isn't just a guy hitting on her, he really does care about her.
With Bender's Big Score taking place directly after Devil's Hands, Leela still has feelings for Fry, she's just trying to suppress them because despite liking him she knows he's... who he is. She falls for Lars because he is Fry, even if she doesn't know it. The romantic payoff in BBS reflects her realization of this.
In Beast with a Billion Backs, Colleen is, like every other non-Leela girl in the show that Fry likes, a reflection of him not being able to succeed with Leela. This leads pretty well into Wild Green Yonder.
It's not like they reset the events of The Sting in subsequent episodes or the movies, it just takes Fry and Leela a little while to actually admit to themselves and each other and get together.
If there's any pacing problems with that arc, it's that they put Bend Her, Obsoletely Fabulous, and Spanish Fry after The Sting. If the season had ended with The Sting -> Farnsworth Parabox -> Devil's Hands, the arc would be much tighter.
