One way to think of this is that the players and the GM are all trying to tell a story together, and dice rolls exist to resolve conflicts between the stories they're trying to tell. Or if you prefer, conflicts between their stories and a world that has other ideas.

It really is conflict between players and the GM, usually. A player succeeding every single roll in an encounter represents a total success for the player. A player failing every single roll in an encounter does not typically represent a total success for the GM, because the GM usually wants the player to be able to succeed. It's much more conflict between the player and world in the vast majority of cases unless either the GM or the player is a shithead and are making the meta-level relationship needlessly adversarial.