The UI should handle it gracefully, for example by deactivating buttons on first click and showing spinners where appropriate. In one case I load required asse

The UI should handle it gracefully, for example by deactivating buttons on first click and showing spinners where appropriate. In one case I load required assets while someone starts filling a form so that the website is ready to generate a PDF when the form is filled. This gives it a minute to load, with fallbacks if it fails.