Wrong again. Jaime for example, he sacrificed his honor by killing the king, in order to save the people of King's landing and put his family (not including himself since he's a Kingsguard) in a position of power.
Cersei is motivated by her children. Her only goal is to keep them safe, but she goes way overboard to the point where she is a crazy bitch about it.
And for the record I would say Jaime Lannister IS overall a good guy. And Tyrion is obviously good too.