1. When your employer (or anyone you do business with) fucks you over. (Bonus if uniform attire is somehow involved.)
2. When a business makes its money from fucking over all or most of its customers.
I just got denied my yearly 10 cent raise because of those times I wore the wrong colored khakis to work. That's business casual sex.
Just got my credit card statement. They raised by interest rate based on my anticipated lateness next month. Business casual sex as usual.