Is your good guy a goody two shoes?

On the flip side of the good bad guy is the good good guy. You want your hero to be good, but unless you are writing Superman you want to be careful just how good that good guy is. It's nice to have a strong moral compass, but which character is the more interesting when it comes down to why they do what they do: Superman or Batman?

My guess is that you said Batman. Superman is a nice noble character, but he was created as a good guy that has too strong of a sense of being good. Batman is flawed, he has a darker side that he must deal with or risk falling into being the thing that he fights against. Batman is a vigilante who is out there because his parents were killed by a street thug. Superman is out there because he has kick-ass powers and has decided to use them for good. Batman has weaknesses, and not just because there is a rock that found its way to Earth, he is human. He has the emotions simmering just underneath the skin, wants to make the bad guys pay for what they do, and yet when he gets into a fisticuffs with someone the person does not have to be super human to kick his ass, just proficient with martial arts and wearing body armor as good as Bruce Wayne's.

But the point I am after is not physical ability, it is that voice in the protagonists head that tells them right from wrong. What made your protagonist decide that they were going to go out and be a good guy? Do they have a little angel and devil on their shoulders? One advising them to let the police have the guy and another that whispers of taking matters into their own hands and not making the public wait out a trial on someone that is obviously guilty. Do they see everything in stark black and white of "this is good, this is bad." Or do they see in shades of gray where they are left to struggle with if things should be better handled by them then and there rather than letting the cops arrest the antagonist?

How do they feel knowing that someone is targeting them? Do they make it personal between them and the antagonist, or do they try to keep out of harms way and let the authorities handle it? There has to be a reason for whichever of those options they elect to follow.

Don't just say, "Well... the antagonist slapped the puppy, so my hero is going to kick his butt!" Give the reader a reason to find the protagonist's reaction believable. Give the reader a reason to think that there was nothing else the protagonist could have done given their outlook on the world. Make the reader sympathize with the protagonist and root for them and if possible, get them to beg the protagonist to listen to one or the other of the little voices encouraging right or wrong actions.

Few things are as exciting as sitting on the edge of the chair and not knowing if the protagonist will take matters into their own hands or will reign in their personal feelings and that flare of anger and let justice take its lawful course.