What Makes Someone a "Good" Person?

I was driving in the Hummer, music playing while running errands, and my mind wandered, as it often does, to my current project. 

For all my books, I love to create a protagonist that is flawed.  Someone that has had problems, isn't perfect, possibly has done bad things, but is basically what I call a "good" person.

Then I stopped my thoughts dead in their tracks and asked, "What is it that constitutes a 'good' person?"  In every book, movie and television show, you have a lead character that possibly had done some very bad things throughout their life.  They have a bit of a colorful past.  And yet they're so lovable, with these little moments of pure kindness or humor or compassion that go against their natural character so vividly that you start to connect with them in a way you wouldn't someone who "always does the right thing." 

I know for me, I always connect with those characters more so than I do the righteously "perfect" ones. 

Is it our actions that make us good?  Abstaining from doing drugs, hurting others, staying faithful; are these all attributes of being "good?"  Or are they societal constructs to simplify the unfathomable complexities of the human composition?  Something to easily define what is "good" and "bad" in a world driven by religion and judgment?

Is it our thoughts that make us good?  Our beliefs?  Our ideals?  Ethics?  Morals?

Are we all just imperfect little creations trying to find our own path, our own answers in the world, driven by our own ideas of what we should or shouldn't be or do?

Or is it possible, just possible, that there is no good or bad?