Not just that, but there is a lot of craft (and state) involved in handling excellent micro-interactions correctly. For example, multi-column dropdowns where you're handling the current selection, keyboard focus & navigation, live filtering, matching international characters in the filter, disabled items, direction of expansion, accessibility...

Each "tiny" feature, when done well, will improve the UX through a small micro-interaction without getting in the way. But together, handling state well becomes an exercise in very careful, thoughtful, tedious programming. Between the tedium and the corporate resistance to long-tail excellence, only a developer who really cares will be able to accomplish it.