To sort of butcher a great line from Layer Cake: “Only very stupid backend people think that the front end is simple.”
Being a more backend-type person myself I have to remind myself that less equations on the human factors side means that side of things is harder, not easier than the “math-y” stuff.
If you've designed a good front-end from an HCI perspective, you'll still end up with sooooo many edge cases. Human behavior is much more variable than the calls sent to an API or SQL sent to a database. (It also helps that there are syntax requirements that limit what's considered valid.)
Being a more backend-type person myself I have to remind myself that less equations on the human factors side means that side of things is harder, not easier than the “math-y” stuff.