If you condition yourself to be OK with 15-25 fps, it's almost fine. If you run a game at 60FPS generally, then an occasional hiccup of 100ms will really throw you off. Similarly, the gameplay must be designed differently between low and high FPS games - you don't want the player to feel like they'd have been able to play the game differently if it was running smoother.
Comments
If you condition yourself to be OK with 15-25 fps, it's almost fine. If you run a game at 60FPS generally, then an occasional hiccup of 100ms will really throw you off. Similarly, the gameplay must be designed differently between low and high FPS games - you don't want the player to feel like they'd have been able to play the game differently if it was running smoother.