The expression x much is a sarcastic expression meaning that the target of the expression is engaging in x, and is generally used when x is undesirable.
An example: Susan is about to leave work at 5:00 on a Friday, and has weekend plans. Just before she heads out, her boss approaches her and asks her to complete a big project by Monday. Susan might say to her boss, "Unreasonable much?"
Another example: a group of friends are eating at a cafe. Most of them are happy, enjoying the food and company. One has been finding fault all evening, saying that the service is slow, the place too loud, the soup was cold, the appetizer oversalted, and the main course overcooked. Someone else at the table might sarcastically ask "complain much?"