You can play a chaotic evil person doing good actions if you rationalize them. Maybe they take the quest to save those innocent people from goblins because now he has a social excuse to slaughter something and inflict pain and while laws were not constraining them the threat of being hunted was. And you can roleplay a lawful good character doing something evil, perhaps he buys a slave off of a slaver because he rationalizes that freeing them this way is better than freeing them by force but all he is doing is rewarding the bad deed of the slaver even if it is legal in that city.
You know what would be an interesting aspect of a game? If someone designed a game that could take such rationales into account.
Clerics can cast the atonement spell -- Shadowheart references it if you ask her if your romance will upset Shar. What if the alignment slider slid but you could offer your rationale to a priest and slide it back? So if you killed all the kids in the grove -- slide towards evil -- but has some reaaallly compelling reason why that was a good idea you could mention it as part of the atonement spell? Since the game has telemetry in it Larian could even have "type in other" and could collect the 'other' responses and revise the game accordingly.
