Each subfield has its own culture and design goals. They both contribute to features that matter to users, but often to different sets of features. The PL community has deep expertise in developing modular, reusable abstractions. The HCI community has deep expertise in developing abstractions that are easy to learn or match the existing mental models of their target users. With rich histories of abstraction design across both fields, a union of these forms of expertise holds the promise of delivering useful, usable, and powerful abstractions.