As both my DH and I put in many years as wait-trons I can assure you that the only times we served incorrectly prepared food was because we were more afraid of the psycho cooks who we had would have to see at every shift than the customer who we would only have to see once in our lifetime.
I worked with some really mean and scary cooks over the years and found that management usually took their side because as a general rule its easier to replace waitstaff than cooks. Also I think sometimes the managers were afraid of some of them as well. At one place I worked at, when the Chef walked out in a snit, the owners changed the locks within an hour and put a sign on the door telling him not to come back, he would get his last paycheck in the mail.
The least amount I will leave usually is 10 percent, unless we the server had the "your not good enough to wait on attitude". Also DH and I are rather adept at deciphering if the bad service was more of a result of bad management (ie understaffing etc) or an incompetent server.
I worked with some really mean and scary cooks over the years and found that management usually took their side because as a general rule its easier to replace waitstaff than cooks. Also I think sometimes the managers were afraid of some of them as well. At one place I worked at, when the Chef walked out in a snit, the owners changed the locks within an hour and put a sign on the door telling him not to come back, he would get his last paycheck in the mail.
The least amount I will leave usually is 10 percent, unless we the server had the "your not good enough to wait on attitude". Also DH and I are rather adept at deciphering if the bad service was more of a result of bad management (ie understaffing etc) or an incompetent server.

