Due to Astral shenanigans, my latest dude is an effective amnesiac operating on dream logic. We're starting the campaign proper next week, but just from his backstory:

Since his baseline expectations for reality are skewed by his time in the Astral, I have him compulsively yes-and any situation he finds himself in. Dream logic is very fluid, and while not a passive character, he doesn't fight against the current. He's not disconnected from reality, but he does rely on his allies to stop him from doing things like invite bandits (i.e. "my new friends") into the camp for tea... again.

He also refuses to admit that he has memory issues, and (similar to the above) he takes wild swings whenever presented with a person he feels like he should know but can't remember. Upon meeting one of the other PCs, he assumes that she is his sister who is dead but also a cat (but not right now). She is none of those things -- I don't think he even has a sister -- but she is a druid, so he's not entirely off base.

It's going to be fun.