Why is imprison preventing me from taking back my turn? It always greys out there options I can't pick anyway so what's going on? My thought process usually involves choosing something and then fixing it when I think of a better play, and imprison is causing me to lose advantage and possibly even games due to this effect that doesn't make sense.
When your opponent has Imprisoned you, you can't use any of the moves that they know. However, the actual game doesn't tell you
which moves those are until you try to select them - which is to say that the fact that you're
able to select a move at all gives you information about your opponent. But remember that you can't cancel your move in the actual game! In other words, which moves you can select is something you can't
know without
committing to use that move for the turn, as long as it's possible.
In the official games, since you can't cancel a move, this actually affects the way that you play.
If you try to use a move, you are
advancing the game state by essentially asking "is this allowed?" or "does my opponent also know this move?" - just by even
attempting to choose a move, you are progressing the game by irreversibly changing what you know and what actions are available to you. If the move can't be selected, you gain the ability to try another one
and also learn that your opponent knows the same move. If the move can be selected, you lose the ability to select a move
in exchange for learning that your opponent does not know the same move. You're always making progress by selecting a move.
On the surface, this doesn't seem all that different from any other move, because you already can't cancel an action in-game - but actually, if every time you
attempt to select a move tells you something, then being able to go back on that lets you check all four possibilities at the same time, which is a tangible difference from the cartridge! Just try to think of a situation when you could use this to your advantage - like if you want to know if the opposing Mew has Stealth Rock, but you don't actually want to
use Stealth Rock. If you're playing on cartridge, you
have to take a risk to find out - if you select Stealth Rock to "test" whether Imprison allows it, and the opposing Mew does have Stealth Rock, then you've learned that information and you still get to pick a move... but if the opposing Mew
doesn't have Stealth Rock, you'll be stuck using Stealth Rock whether you like it or not. On Showdown, if you could cancel your move, it would just be a matter of being fast enough - you could click Stealth Rock, see that Mew doesn't have it, and then back out and pick something else anyway.
That's why Showdown doesn't let you cancel certain actions in cases like this - because it would actually be changing how the game works and even allowing you to "cheat" just to accommodate for it, whereas normally it's only a matter of convenience.
(It's the same reason that you can't cancel a switch if you're facing an opponent that might have a trapping Ability or might not, like Gothitelle - if the game
showed you that you could switch and then just let you cancel, you would
know that you weren't trapped but could still carry on with some other move, whereas if you were playing in the real game, you would have no way to confirm that it didn't have Shadow Tag if you wanted your action that turn to be an attack.)
