Why do there actions necessarily need to come out differently? The rules only require they act like the caster is a friendly acquaintance. Maybe they just sometimes attack friendly acquaintances, or run away from them in fear? Who is to judge that those aren't the thoughts a character might have to a friendly acquaintance?
Why should a DM ever expect anything from a character who has been subjected to a Charm Person and how would it be adjudicated without requiring the player to explain what the character was thinking (seemingly contra to half this entire thread)?
@iserith , for example, said they would leave it fully up to the player (see #963) to decide what was appropriate. Would your table differ?