200ms delay is easily noticeable. Even 50ms is noticeable. And latency is cumulative, and your user's hardware already adds some, so you never know exactly how

200ms delay is easily noticeable. Even 50ms is noticeable. And latency is cumulative, and your user's hardware already adds some, so you never know exactly how much latency budget you have before the whole system feels unpleasant. I think 25ms is a reasonable goal, and even 10ms wouldn't be a waste of effort. All interactive software should be written like a fast-paced action game.