I find that most players do not properly appreciate the practice and usage of supernatural power in the form of magic. Getting too focused on the mechanics of play, especially when playing a tabletop RPG, denigrates the power of this specific genre of game. As I said yesterday, RPGs in particular are an unstable mix.
Just as too much Story--narrative logic--perverts the gameplay by damaging the vitally-important sense of verisimilitude, ignoring the milieu and how the player-character interacts with and experiences that environment by focusing too much on the mechanics of gameplay also perverts the gameplay by removing the focus of player attention upon natural-language engagement with the milieu as the primary mode for the RPG Gameplay Feedback Loop (aka "What do you do?"). You can't get emergent phenomena in virtual experience if you're too concerned with the code for the program (mechanics) or fixing the results (story).
Nowhere is this more of a problem than when dealing with supernatural power or items that wield it (and yes, this includes science-fiction RPGs, but we're using magic because Fantasy is the RPG standard). "My Wizard hit 5th Level, so I'm taking Fireball because Page XX says I can." is bullshit, and the games that make this a thing do so because they do not trust the Game Masters that run them. (Such rules have a place in convention-based Organized Play environments, which is as close as tabletop RPGs get to videogames, but home games are not that and TRPGs need to stop writing on that assumption.)
The study, practice, and use of magic should require the player to engage with the milieu through their character. Acquisition of new spells, rituals, items, etc. are--and should be--viable gameplay scenarios at the table. They should be played out at the table. Finding the relevant information, dealing with someone else who knows what they seek, or putting in the work to figure it out for themselves are all interesting and relevant objectives that should not be waived away. Knowledge of consequential things is a treasure unto itself. It should be handled accordingly, both at the level of player engagement with the milieu and at the level of Game Master adjudication of gameplay.
(Yes, this should be done with non-magic things of similar consequence; again, magic used here because Fantasy in the standard for RPGs.)
The result is that the player is required to think and behave in a manner consistent to what his character would have to think and behave in order to succeed, which is why the RPG is the best medium of Virtual Life Experience that gaming has yet produced. You play the way your character would act..
(Yes, it's a variation of "Train the way you fight.", and that's a proven method for getting proper mindset established in good habits.) You want to play a Wizard, then you damn well better start thinking like one and not like a robot jock whining about upgrades to his mech chassis.
The reason I'm about this right now is that ignoring it plays into the hands of those who cannot distinguish tabletop RPGs from their alternatives, and therefore favor those because the alternatives do what they think RPGs are better. I'm staking out turf that, to this day, only a tabletop RPG can do well: natural-language emergent-gameplay sandboxes with no metagame-defined conclusion, the Virtual Life Experience effect at its fullest power. Narrative logic perverts this as surely as mechanic-obsessed autists do, to their detriment and those of the hobby as a whole.
But when that player, playing that wizard, finally groks what his character's mindset and paradigm is about fucking miracles happen. He sees from a perspective that (a) is NOT his own, and (b) is no less real than his own. It is the application of the same psychology behind initiation rites, but for a related purpose. Gaming, remember, is derived from training exercises; failing to embrace this as a desirable thing is failing to make the most of what is on offer- and I want that magic to happen. Literally.