this being the first true conversation between fionna and finn is an amazing choice imo. it’s a conversation where each verbalises how they feel about their shortcomings (the real ones and the ones which solely exist in their minds), with a level of vulnerability that they’ve been struggling with a lot up until now. the fact that this takes place literally inside finn’s heart adds to that vulnerability even further.

we’ve seen them struggle to break the habit of engaging in self-sabotage. for finn, it’s the constant jumping from one ‘adventure’ to the next, while skirting around the possibility of fully processing his grief for jake. for fionna, it’s the pursuit of things that haven’t worked out for her, blindly hoping that she’ll have more luck this time (i.e. her relationship with phelix), or diving head-first into whatever she perceives as ‘the right thing’ as a means of proving herself. we also know how much trouble this has landed them in, with finn being on the verge of death and fionna having lost her closest friends.

so, them talking about all this so openly with each other - with themselves - is that final push they needed to keep going. to give them a better understanding of themselves and the people who matter most to them.