One of the worst feelings is building a site without a view library like React, getting 80% there, and then realizing you absolutely need dynamic functionality and/or state management because the project's scope changed or started calling for it, only to realize you now need to refactor much (or all) of the site to make it easier to maintain across the board.

This is why I reach for a view library like React, Vue, or Svelte, even if I'm creating something simple. This is because I'm familiar with using these and they provide me with the ability to implement nearly any kind of dynamic functionality or interactions I could want, fine control over component lifecycle, and tight integration with my CSS library of choice to speed up development.

End-users are none the wiser, that is of course unless I do a terrible job using these tools.