I prefer mysteries that are actually mysterious. I don’t think pretending to be surprised the first time a wizard casts magic missile is particularly fun or interesting.
While I consider that roleplaying a PC.
This is worth unpacking. It reveals some of the differences in underlying assumptions. Maybe what we're talking about here is the difference between actor stance, director stance, and some other stance...although to be honest I'm not 100% positive what those terms mean.
I could agree with Salthorae (in this example) if there's a strong connection to the character concept. Let's say the character comes from a land (plane, era) without magic, and is astonished at all the wondrous things he/she discovers in this new land. In that case I think it would add to the experience at the table if the first one...or maybe two...times somebody cast a spell that player roleplayed wide-eyed amazement. But, again, it would have to be done in order to highlight an important trait of that character. And then once that narrative point is made, that's enough. I would either want to see new ways of drawing attention to that facet of the character, or (better yet) see the player highlight other facets I haven't seen, which may even be brand new facets they that reflect their character's evolution, even if it's just because they thought of it that moment, opportunistically.
In other words, if it gets to the point where
I can predict what a player will do in order to roleplay their character, I've lost interest in seeing/hearing it. "John just pretended to be amazed by a spell again. Oh joy."
And if there isn't a strong reason why the character would be especially surprised by a magic spell...that is, if he/she is your typical adventurer from a magical fantasy world and would be no more nor less amazed by a spell than any other typical adventurer, then I would think that roleplaying that facet is, to be totally honest, a complete waste of precious table time.
Even if that's what a person might likely to in that situation. It's just not...interesting.
But I get the sense...from this and many other threads...that what some players like to see is consistency. That the ability to constantly be "in character", doing things the way that character "would do it", is the mark of good roleplaying.
Is that accurate?