Improving the way non-player characters perform was Bethesda's "number one focus" for upcoming fantasy role-playing game The Elder Scrolls V: Skyrim.
Design director Todd Howard told Gamasutra the developer still struggles with how NPCs act.
"The big things for us are still - and we still struggle with - the NPCs, the interaction, and how they act," he said.
"That's because the game is so dynamic, we don't want to script them, so weirdness can ensue sometimes. So we came out of Oblivion thinking, hey, how do we get more believable characters on the screen who are reacting to you?
"I always thought we did environments well, and we want to keep doing it well. But I'd say the characters and how they perform on the screen was probably our number one [focus]."
Bethesda's open world games are famed for their open-ended gameplay. This, according to Howard, means sacrifices must be made elsewhere.
"There's going to be some [weirdness], like the player did X, Y and Z that we didn't expect, and now he's attacking the town, sleeping in this guy's bed, he killed his wife...
"We sort of learn each time how people play these games and experience them. So we get better each time, but we do at the end of the day sacrifice, say, a well-paced story. It's almost impossible for us to do. We'd rather let you go do whatever you want. So that's a sacrifice that we're willing to make."
And on the subject of bugs and the often-hilarious videos of them that are available online, Howard is philosophical.
"You know what though? Those things are there, and it's fair that people call us out for them, we've got no problem with that."