I want my stuff to work on mobile web. What I don't want is for stuff to look like it worked on mobile web, because the front end is "optimistic", but it actual

I want my stuff to work on mobile web. What I don't want is for stuff to look like it worked on mobile web, because the front end is "optimistic", but it actually didn't work. I find this to be a much worse user experience than having to wait for a round trip most of the time.