Whoops finger slipped and that went on the corporate card; well, there's a $25 charge to transfer an accidental charge.
Or
Whoops finger slipped and that spouse christmas gift went on the shared expenses card. Well, if you don't want her to find out early, there's a simple $25 convenience fee to transfer to a different account.
Or
Whoops paid for the new snowblower in "cash" using direct debit from the checking account instead of the credit card. Woo hoo thats ten bounced checks at $50 pure profit, err, I mean, "fee", each!