Not putting your kids needs first.
I think overall you should put your kids needs first but on a day to day basis there are times I need to put myself first or I'd go insane. For example, there are times that my need for five minutes to sit down and eat my breakfast trumps their need for me to amuse them like some sort of on-tap entertainer.
In the grand scheme of things a 'good' parent has children who are fed, clothed, loved and cared for, and they have reasonable boundaries.
'Bad' parents are neglectful, abusive, choose not to provide adequate food or clothing, have absolutely no boundaries because they simply don't care where their children are or what they're doing.
I'm an optimist and I like to think that most parents fit into the 'good' category.
Ultimately, we're all making it up as we go along and if there was any one parenting method guaranteed to produce healthy, mentally well balanced adults then it would be the only parenting method in existence.