"True Love" is a tricky concept in the Once Upon a Time universe. It's a concrete thing, not just an idea — it can break curses and even be bottled. Yet at the same time, its rules are slippery, and it's thematically hard to define. That can get confusing, since it's also at the center of almost every character's story.

Here are some of things we find perplexing about how True Love works on OUAT.

How common is it? Every character on OUAT seems to have some grand love buried in their backstory or coming up in their future, yet Emma (Jennifer Morrison) has all sorts of unusual powers which, according to Mr. Gold/Rumplestiltskin (Robert Carlyle), are the result of her being the "product of True Love."

Assuming Gold isn't flat out lying, his surprise and confusion over Emma's powers suggest that she's pretty unique. But shouldn't a lot of Fairytale Land kids be products of True Love? For instance, does Cinderella's (Jessy Schram) kid have special powers, too?

Are Snow (Ginnifer Goodwin) and Charming (Josh Dallas) in some sort of Extra True Love, and perhaps that's why Emma is superpowered?

Is it only once in a lifetime? If so, how do kids fit in? Regina's (Lana Parrilla) entire downward spiral was provoked by Snow and (mostly) Cora (Barbara Hershey) supposedly destroying her chance at happiness by killing her True Love, Daniel (Noah Bean). That would suggest that True Love is a once in a lifetime deal — you mess it up, and you're condemned to a life of less-than-perfect happiness.

That alone is a pretty depressing concept, and would seem to bar several characters — certainly Regina, quite possibly Ruby/Red (Meghan Ory) and Hook (Colin O’Donoghue), if you believe their respective dead loves were True Loves — from ever achieving full happiness. For that reason alone, we hope it's not the case.

On top of that, you have Emma's love for Henry (Jared Gilmore) breaking the curse on Storybrooke, which adds a whole new variable to the mix. If parental love also counts as True Love, don't many people have multiple True Loves? Even if you only get one romantic True Love, you can still have many kids...

This seems like a good sign for Regina (and certainly ties into her attempt to redeem herself for Henry), but it also muddies up her backstory, since it makes True Love far less rare. And what about Rumple? Yes, he loves Belle, but he loves Bae just as much, if not more. If that counts as True Love, why didn't the Blue Fairy (Keegan Connor Tracy) suggest Bae try giving his dad a peck on the cheek before going with "portal to another world"?

Does it have to be reciprocated? This is less confusion, and more curiosity. In Season 1, Sheriff Graham (Jamie Dornan) began remembering his past because of Emma's kiss, which would suggest a "True Love breaks the curse" situation, but it doesn't really seem like Graham is Emma's True Love. Could she have been his, anyway? (Of course, given her other powers, this could be a moot point — perhaps his memory returning had less to do with love and more to do with other magic).

There's no clear answer to these questions, yet, and maybe there doesn't need to be. It's possible that True Love is a flexible concept meaning different things for different characters. Perhaps Snow and Charming's love is extra special because they were willing to fight so hard for it; maybe Emma's love for Henry broke the curse because it was so hard for her to open up and love anyone.

Still, we'd love to hear what you make of the True Love concept, and how you think it will continue to work as the show goes on. Sound off in the comments below!

Catch the next episode of Once Upon a Time on Sunday, February 10, 2013 at 8 p.m. ET/PT on ABC.

Rebecca Martin is an editor at Wetpaint Entertainment. Follow her on Twitter @BeccaDMartin.