The Fundamentals The Next developer The Database
Worst Case Scenario
Dowitime is not the worst case, nor is a UI bug, even if users leave over it.
Instead, I would be thinking about effects that are outside of the application domain: leaked private data, duplicate bank transactions etc, and un-recoverable errors: data corruption / loss.
Of course, that's a generalisation, worse case will be different for different applications. If your job is to alert the population about natural disasters, downtime and accuracy are 100% the most important factors. Somewhere within me hopes that if that is your job, you aren't reading an article on startup code. But maybe you are responsible for a huge sales event, or something like that.
I'm also not talking about 'all the time' - reliability might be an important value for the customer -