Using Svelte and building global state classes with $state(), $effect() has really helped with managing side-effects and surgical updates without building a custom event system which has historically added unnecessary boilerplate to many of my projects with a frontend.

Having components bound to or using any of the $states or $derived update automatically without having to manually register event listeners, firing events, etc.

Used to dislike runes so much initially, but working a bit more deeply with them has really made me appreciate the API changes.