This video is a great introduction to ttrpgs in general, but at this timestamp (23:08) has some particularly good GM advice on some of the points raised in this thread
edit: also, just to elaborate a bit, basically the advice is when a player asks "can I do X," the GM should avoid simply saying "no." Notably, the examples given (strong implied context of dnd) are either not things covered in the rules (e.g. drinking a sip of a potion), or are places where the rules are punitive to the point of discouraging the action (not to mention buried in long rulebooks).
edit: also, just to elaborate a bit, basically the advice is when a player asks "can I do X," the GM should avoid simply saying "no." Notably, the examples given (strong implied context of dnd) are either not things covered in the rules (e.g. drinking a sip of a potion), or are places where the rules are punitive to the point of discouraging the action (not to mention buried in long rulebooks).