Who's the most unprofessional employer/employee?

Monica - generally pretty professional, but she did get fired for accepting free steaks from a supplier

Chandler- choosing not to fire his colleague so he could keep dating them (Nina) isn't ideal Also neither is trashing your own office (although that's partly Bob's fault)

Ross- sleeping with Rachel at his place of work (and staying there overnight!) Dating Elizabeth while she was still at college

Joey- sleeping with the extras on his show as well as sleeping with a casting director for a part.

Phoebe- biting her massage client! And then making out with him at work

Rachel- hiring tag instead of the qualified assistant. Breaking into Joanna's locked office (ok she had keys but you know what I mean)