They're close in canon and clearly feel comfortable around each other and they have a good deal in common, neither of them are perfect and they both have flaws but they're able to deal with each other as they are. Both of them are such dumb dorks, and there's potential for complicated messy situations in their relationship too because of both of their flaws and their shared history, even in canon their relationship hasn't been all sunshine and daises after all. A good amount of history to explore too.