Me making my devs create a base exception for handling all exceptions that contain messages for display in the UI. Which has a parent base exception we use for all our exceptions which of course has Exception for it's parent.

I hate our codebase but I'm so close to killing off 15 year old vb.net code. If the left me alone and I had the time I spent in meetings or 20 mins between meetings everything on our roadmap for the next year would have been done 2 years ago.