The only widely known philosophical idea that I think that I have heard that is actually bad is "Patience is a virtue". If you really take this idea to heart, you basically just end up sitting around your whole life waiting for something that never happens. Someone that is a real go "getter" will always beat you to everything you are waiting for to happen.
Maybe, it would be better if instead it was, "All patience is worth while of being is a virtue". Then that may be the reason why people stated it to be that to begin with, because that is the only thing they could actually conclude what it actually is in every case. Then maybe it was actually a good philosophy, but it just creates stumbling blocks down the road for the person hearing about it.
It doesn't actually have to provide a positive outcome on your life to be a good philosophy. It only matters if that it got you to think about something more deeply to arrive at a better conclusion or understanding of the world around us. That it has accomplished.