That's actually an interesting question. Aside from problems that are easily observable as difficult because lots of smart people have tried and failed, how can one objectively know whether it was difficult or easy?

Even within "just a web app" one can run into some gnarly issues or odd old code that renders otherwise simple tasks difficult, but since it's only one person working on it you can't really test whether or not it's actually difficult.

This might impact both the dev/manager disconnect as well as imposter syndrome.