McTard
McTard is a shorter version of McRetard.  A McTard is a disparaging term for a McDonalds, fast food employee or persons other bottom-level end position service related.

McTard is also a derogatory term referring to those with mental disabilities, mentally challenged and mentally handicapped persons working at McDonalds or food service related jobs.  

That McTard couldn't get my order right, so the manager had to take my order!