Forgive me if I over think this, I have a tendency to think deeper the question sometimes. In life being a good or a bad person really depends on one's perspective, for example Robin Hood, according to the tales he was a good guy. Robbed from the rich and gave to the poor. Now one version I have read. Truthfully, him and his merry men were bad guys. They broke the law, they stole from the rich and they had no qualms of killing to get what they wanted. Now some would say they did that to protect the people and that they gave all their loot to the people. Some believe that they actually shared their bounty for 2 reasons. 1st, to buy peoples' silence. You give a starving person food and eventually the will follow you like a puppy begging for scraps. 2nd, they had to be constantly on the move. Too much bounty is hard to move, so they only kept what they could carry.
Now GTA 5, Michael and Franklin, I treated as they two people that just made bad choices. I never took a life when playing them that I didn't have to. Now Trevor, I really didn't like playing and yes I treated him like he was psycho all the time.
Normally being a white hat kind of guy if I can be I imagine I will play him the same way I did Michael and Franklin, but Rockstar has a tendency to put characters in bad situations.