App context is a simple todo task app.
So, what would be the best way to convey to the user the task already exists on the list?
Basically, I want to keep the message and prompt as humorous and less annoying respectively.
Best way has fulfill two needs:
This is best done with an alert, typically. The language you use is up to you. I'd suggest something like "D'oh! You already have [taskname]"
But be aware of the usability challenges associated with it. Does the alert offer a way to retain the data, meaning return to edit? If not, what is the action?
In my experience the language is important but the functionality wins the day. Or, the way I think of it, users come for the functionality but stay for the form.